Pagoda Dogwood should work.

The sympodial branching of Sassafras is also quite attractive.

Cockspur Hawthorn (Crataegus crus-galli) has nice horizontally-tiered branching. Fall color is also quite good.

What killed the maple? Has the stump been ground out? Testing of declining big-leaf maples in the Seattle arboretum some years ago showed multiple root pathogens being on them (but see also at link below). If the same thing happened to your tree and there is an intact stump still present then new plantings nearby might become infested also. Particularly if there was a honey fungus (Armillaria) involvement. If such concerns seem applicable the stump should be dealt with before time and money is put into new trees being installed on the same part of the property.

Bigleaf Maple Decline, Update and Next Steps

https://dnrtreelink.wordpress.com/2016/08/10/bigleaf-maple-decline-update-and-next-steps/

Two arborists said the tree was healthy and that this happens with multi trunks as they age.

We are going to leave the stump.

Thanks everyone for all your suggestions, I’m going to look into all of them. I did like the look of the hawthorn but I definitely don’t want thorns.

If horizontal branching not a definitive requirement, your choices could expand almost exponentially :-) This is a listing compiled by PNW horticulturists and nurserypersons of tree species and cultivars that are highly recommend for PNW gardens - Great Plant Picks - Trees. In fact, the entire GPP website is an excellent resource for PNW gardeners.

What about a mimosa?

Ooh, I like that a lot. Have you seen that in any local western wash nurseries?

There are also magnolias, that come in countless varieties with different color flowers.

Or Chinese plum. (which I would suggest getting non-grafted, growing on its own roots, if you want it to grow to medium size, usually planted as a small seedling but they grow fairly fast)

If you want evergreen, two other unusual options are Cork Oak or Deerhorn Cedar (the latter of which has a pleasant aromatic smell). Both of these only grow to about medium size.

Mimosa = silk tree, Albizia julibrissin. Not an uncommon tree here at all and should be found in season at just about any better larger garden center and nursery here. Has a reputation for being somewhat tricky to establish and does not have the same weedy/invasive nature here it displays elsewhere. And can get to a pretty good size. There is one in a Wallingford neighborhood that is massive, with a canopy extending completely over the street.

One in Vancouver, WA had a trunk 7 ft. 5 in. around and a 72 ft. average crown spread in 1990. Maybe you are talking about one listed by A. L. Jacobson in Trees of Seattle - Second Edition (2006):

Bagley Ave N, south of N 39th St: a street-tree, W side, 41' x 6'8" x 67' wide

where he also says

It's common here, reaching about 45' x 6 1/2' at best, then usually dying--or being chain-sawed into such ugliness as ought to be illegal. After a frost or two in November, Silk Tree becomes "sulk tree,", appearing forlorn and bedraggled, like a fancy new hairstyle caught in a thundershower. While other trees exult in vibrant autumn color, it pouts, limp and miserable, drably aching for its more tropical homeland

There was a gorgeous silk tree/mimosa planted in a little park by a major intersection in Olympia that was so stunning - my first experience with them. The road ended up being widened and it had to be moved; I think it survived but it's not as viewable from the street now.

It would be a great choice, I think.

Also prone to a consistent dying back of small interior side branches in our climate, often more or less throughout the specimen. And quite late to leaf out in spring. For us it produces a unique effect in flower, and it is certainly able to reach some size here (in suitably warm and sunny planting sites). But there are definite limitations involved with planting one of these in this region - when growing on a local site where multiple other decorative trees and shrubs are present a silk tree will often stand out markedly. With this frequently not being in a particularly attractive way.

Haven’t had time to make a final decision yet-still cleaning up the maple tree damage. Thank you everyone for all your suggestions-it will be fun to figure out what I’m going to get!

Just a late fyi on the mimosa consideration - once they achieve some size to flower nicely, which smells heavenly, the spent flowers shed all summer long and are NOT easy to clean off any plantings underneath. You pretty much have to hand-pick them off your plants.

How well do beech trees grow out there? Some nice color choices, with fairly horizontal branching, and maybe slow growing enough to not outgrow its spot in your lifetime?

What about Stewartia? I favor monadelpha. Here's one of mine a few days ago. It's the tree in the center.

Definitely no to mimosa than-I have enough clean up from my maples!

I will look into beech but is stewartia horizonta? I can’t Tell from the picture.

Shedding flowers "all summer long" is a bit of an overstatement :-) First, they tend to be very late to leaf out....often appearing rather dead looking well into April and early May. And only bloom here for a short stretch....mid July into early August, typically. And shed no more than any other flowering tree.....I don't find them to be problematic in that regard at all. But they are a bit messy in fall when the leaves drop as they shed the long rachis the individual leaflets are attached to as well. But again, no more or no less messy than most other deciduous trees.

Stewartias do not tend to have a very horizontal branching habit. But they are stunning trees and offer a full 4 seasons of interest!!

I am also tempted to move a young Pink Lady apple tree that I already have over there. It wouldn’t cost any money and the place the apple is now is just meh....

Think it’s too late to move it now?

Let me try to tempt you with Prunus mume again. Pictures here and here.

Socal, is that a crabapple? I also want a showtime crabapple that I haven’t found room for yet.

No, it's not a crabapple.

Prunus mume goes under a few different names, perhaps the most common of which is "Chinese plum", although it is actually more closely related to apricot, not plum. Some varieties have fragrant flowers, which smell like plum. Actually Chinese plum used to be more popular in China long before cherry blossom trees became popular in Japan, and today the Chinese still tend to prefer their flowering plum trees.

Ok, off to research Chinese plums....

Stewartia monadelpha can have the layered look with just a little pruning. I always worry about snow loads with layers and keep that in mind when pruning..

The stewartia develops a layered appearance without pruning, is not the kind of tree that lends itself to much pruning.

It is the kind of tree that may die during a dry summer here if not watered.

The dominant English common name for Prunus mume in my experience is Japanese apricot.

Plant of the Month: March 2005 - Japanese Apricot Prunus Mume (Sieb.) S. & Z.

http://www.arthurleej.com/p-o-m-Mar05.html

Two reasons I can think of for it not being seen much on local properties are occasional episodes where much of the tree blights off in spring - but seems much better able to grow back afterward than simultaneously affected Higan cherry cultivars - and the main supplier of finished garden center sized specimens of named cultivars with good quality flowers grafting them onto an apparently incompatible root-stock. Resulting in rapid and marked failures of the scions just about when the trees are starting to get some size on final planting sites.

And seed-raised examples sometimes producing tiny flowers and shoots lined with spiny spurs.

The season for digging up an existing planted orchard apple starts in November, after the leaves are off. However I have to wonder about Pink Lady being adapted to the local climate - have you seen any information from serious sources like USDA Cooperative Extension indicating this?

Also what about cross-pollination, is there a suitable pollen source for this cultivar on your site? A mantra is that orchard apples require cross-pollination to fruit well.

Embothrium, I honestly didn’t do any research when I got the Pink Lady. I just wanted an apple my husband and kids would like. I also bougjt an espalierred apple with gala, honeycrisp and one more I can’t for the life of me remember right now.

If I moved the Pink Lady it would be closer to the espalliered tree.

The convention is that specific orchard apple varieties have to be paired up to achieve cross-pollination. Presumably, if commercially grown - and all of the cultivars present at time of purchase are still part of the specimen - your "combo" apple consists of kinds that will fertilize one another.

Any one of them happening to be cross-compatible with whichever particular cultivar was sold to you as Pink Lady*

https://en.wikipedia.org/wiki/Cripps_Pink

is another matter.

However it is also said that much of the problem is different orchard apples not all being in bloom at exactly the same times. With this being overcome by planting representatives of the longer-blooming flowering crab-apples in their midst - this is why kinds of these can be seen planted at the ends of rows in commercial apple orchards.

So if you go ahead and get your Showtime ('Shotizam')

http://www.lakecountynursery.com/lcns%20sell%20sheets/ShowTime.pdf

and add it to the mix you may be covered that way.

As far as pollination is concerned.

*Note also at page linked to above:

Cripps Pink apples are the earliest to blossom (late March/early April in the Northern Hemisphere and late September/early October in the Southern Hemisphere), and some of the last to be harvested (end of October/early November in the Northern Hemisphere and late April/early May for the Southern Hemisphere). It is the significant change in temperature between night and day in the autumn that gives the apples their colouring. However, they must also be well exposed. Therefore, the trees must be carefully pruned and their fruit production well managed.