With your raised retaining walls, there is not enough room for tree roots in your yard. It would only take a couple of years for the roots to start breaking down the barrier. I would suggest shrubs instead. However, I would check with your local nursery or Google before planting. Some shrubs can be invasive and damage your retaining wall as well.

phun...is right. You simply cannot plant a tree (or any large shrub) that close to the retaining walls. You could plant something small, like a Japanese maple or even a small myrtle centered front to back and to the right of center side to side.

For trees in either location, look for ones whose roots go down rather than spread out toward the surface (different trees have different kinds of root systems). Spreading roots will kill your driveway and sidewalk. I don't think you should put one between the sidewalk and drive--not enough room.

And, whatever you do--no ornamental pear trees (Callery or Bradford pears)! Pretty, but short-lived and weak.

One tree on the left hand side of your yard to anchor the house - like Yardvaark shows.

Thank you... nothing in the center to help break up the concrete and provide a little more privacy from the street?

You can break it up with low plantings, a small scale specimen shrub, or a stone wall cap. I wouldn't plant another tree. Landscape design looks better with odd numbers.

If you want more privacy, move the shrub border to above the retaining wall and underneath the tree, away from the house. There are shrubs that will do well in that circumstance. Low fragrant sumac comes to mind . . . don't know your zone. Some of the larger shade tolerant grasses . . . I'm not a fan of landscaping hugging the house, attracts pests and moisture and tends to outgrow its space and becomes a problem. The sumac is aggressive but can be easily pruned to keep in line.

"... nothing in the center to help break up the concrete..." Center of lawn ...? And how does that "break up" concrete? I'm stumped. Maybe you need to describe in a different way.

"... and provide a little more privacy from the street?" I've looked at the illustrations you submitted in your introductory post and do not see anything that I would term "privacy" since I can see the door, windows, path from house to car and house to street and front lawn. Please explain what you wish to be private and from what view as nothing currently looks off limits. While some people do make their front yards into private spaces, it does mean a visual, and probably physical separation from the street. Is this your intention? If so, why?

We're pouring a new driveway and walkway because current is sinking and drains towards foundation. We're going to have a small strip between driveway and walkway we can add plants, was hoping to break up the big concrete slab visually with something (like a tree). Also, by putting a tree or something there, we create a bit of privacy from the street since we've got glass entry doors. I tried to capture this in the drawings from the original post. Thanks!

If glass doors seem not private enough that problem should be solved inside the doors with a gauzy curtain allowing you to see out but limiting others seeing in. A tree centered in that zone is going to work against you in so many ways. It's just not the place. Nor will it be the solution for visually "breaking" up an extent of paving. What you need for that is decorative elements being part of the pavement itself. Move the tree to as far right as the center of the lawn area if you like. But then another tree ought to be at, or in the vicinity of, the other side (right) of house.

So far, you're working with the picture of half a house. This is really not how you go about creating a unified landscape for the whole front of house. You need to be working on the whole picture at once. Even if you do nothing at the right side, you should be accounting for what's there. Any designer would.

Since you're thinking crape myrtle and pistach and your 2nd photoshopped photo (which I prefer) looks like you incorporated drought tolerant plants, I'm wondering if you're in CA. If you are you might want to look at western redbud, I'm not sure about its root habits so check with a pro on that. I also love small Japanese maples if they suit your zone.

Love this photo with cercis occidentalis and ceanothus:

[https://www.houzz.com/photos/mostly-native-california-garden-landscape-phvw-vp~30450344[(https://www.houzz.com/photos/mostly-native-california-garden-landscape-phvw-vp~30450344)

and some articles on houzz about small trees/limited planting areas:

[https://www.houzz.com/magazine/great-design-plant-cercis-occidentalis-for-four-seasons-stsetivw-vs~48467587[(https://www.houzz.com/magazine/great-design-plant-cercis-occidentalis-for-four-seasons-stsetivw-vs~48467587)

[https://www.houzz.com/magazine/10-spectacular-trees-for-courtyards-and-tight-spaces-stsetivw-vs~80620610[(https://www.houzz.com/magazine/10-spectacular-trees-for-courtyards-and-tight-spaces-stsetivw-vs~80620610)

[https://www.houzz.com/magazine/5-best-behaved-trees-to-grace-a-patio-stsetivw-vs~3798249[(https://www.houzz.com/magazine/5-best-behaved-trees-to-grace-a-patio-stsetivw-vs~3798249)

[https://www.houzz.com/magazine/pretty-trees-for-patios-paths-and-other-tight-spots-stsetivw-vs~31743372[(https://www.houzz.com/magazine/pretty-trees-for-patios-paths-and-other-tight-spots-stsetivw-vs~31743372)