I'm pretty sure you won't like this answer, but I wouldn't do any of the things you're thinking about. I wouldn't want something taller, or barely taller than the porch floor ... unless it was something that has wispy flowers at a higher level. So, for me it would be some kind of solid groundcover. One that bloomed would be nice. People are not going to offer specific suggestions unless they know where in the country/world you are.

Your roses aren’t doing well for one reason that I can see: they are extremely close to the porch. I never plant a shrub closer than 2 feet from a structure - usually at least 3 feet away.

Everything but the bluebeards/Caryopteris will be a good sized shrub and will be too wide and too tall leaving the front of the house looking buried and the path unusable. An 8’ shrub cannot be constrained to that size space via pruning, and I agree that you don’t want plants much over the height of the porch floor unless it is really airy.

A bit more info please so we can perhaps see if the reason the roses failed may apply to other plants:

Would you add a photo that includes the roof overhang?

As Yardvaark requested, location? My memory is Utah or somewhere in that region. Irrigation water may well influence what you can grow there if the pH is high or there are salts. Have you had the water tested or is that info available from the local supplier if you aren’t on a well?

What soil prep was done for the bed? Often foundation beds include leftover concrete or the washings from the concrete truck or other construction debris and/or are highly compacted subsoil which is a tough growing situation for all plants. For foundation beds on newer construction one often needs to dig in a lot of organic matter and remove construction leftovers.

Check out Magic Carpet Spirea & Pink Bergenia as an evergreen underplanting.

I would not plant any type of shrub there. Heuchera and Hosta would be nice if they grow in your zone.

For a cottage look I would make that area a bed of perennials and fill in with seasonal annuals. Irises and bulbs for spring and mums for fall. Flowering ground cover like Ajuga and creeping phlox would keep things low growing in the front. A bit of evergreen would be nice but maybe there is a herb like rosemary could be used instead boxwood. It depends on your climate.

I don't know where you are, but in my region, burning bush is an invasive and shouldn't be planted. The other shrubs I think generally want to be large, although I have a 'summer snowflake' viburnum that lives under a large tree with a few other shrubs & perennials which has stayed small.

You might consider building more of a planter structure with stone or bricks, replacing the border rocks, to elevate the planting bed a bit in order to get the effect I assume you want from lower growing plants such as the heuchera and hellebores suggested.

I have both a variegated weigela and an ornamental quince that I keep fairly small with pruning & they are doing well. Also there are dwarf conifers out there that might suit you.

'Summer Snowflake' viburnum has the potential to get quite massive!! Here, it will easily reach 8-10' tall with an equal or slightly wider spread. Much too large for this situation! Keeping flowering shrubs unnecessarily small by pruning usually results in very halfhearted flower production.....if you get any flowers at all.

I also agree that all the plants that you list will grow far too large for that area. If we knew where you were located, we could make some suggestions for truly dwarf shrubs that might fit that situation. Right now the only shrubby suggestion other than boxwood that would work and will grow in most zones is the Magic Carpet spiraea that Doug suggested. Even 'Little Princess' gets too big.

Look into Dwarf Fothergilla. I have 3 of them. At first they were in mostly shade, then I had to move them because of total landscape change. Now they're in full sun. They do nicely in either. Mine are at least 10 yrs old ( maybe older) and they're about 3-4 ft high.

Gracie, where are you and where is the OP? If she is in the mountains or high plains of Utah or NM, the thin atmosphere, dry air, and alkaline soil will make fothergilla impractical, though they are one of my favorite plants. That is why reesepbc was asked about location beyond zone.

how about some clematis on trellis.. though i would figure out how to anchor the trellis.. so i didnt have to literally attach them to the posts ...

ken

https://duckduckgo.com/?q=clematis+on+trellis&t=ffcm&iax=images&ia=images

I would suggest Hosta or Heuchera. There are several colors and patterns that you could make a very attractive border. Spring flowering bulbs, some columbines for early summer interest, may be some lavenders. You could do one or two trellises of Nasturtiums - in front of the pillars for some height .

Some varieties of coreopsis are shorter, as are some carnations - both are perennial in 6a/6b where I am .

I was tempted to suggest Magic Carpet spirea also, because they stay small and they are colorful shrubs. I have three myself. Two things to consider with this one. One is that there is a chartreusey yellow in the leaves, which also include greens and coppery colors. The question is would this work with the yellow on the side of your house. The other thing is that the flowers are kind of a purplish pink and they bloom around the same time as roses in June. So the question is what color are the blooms on your roses and would this work or clash?

Spirea doesn't bloom that long though does it? How about small hydrangea like Endless Summer?