Newbie and zone 7 front yard flower layout help

I'm trying to turn my front yard into a place I can grow roses and a cottage type garden, the dogs and the vegetable garden get the backyard! My front yard faces west and is sunny except for by the porch where there is a small overhang. Last year I planted coral bells there and they have done okay I think, even the one that gets all the water from the corner of the gutter above dumped on it. I planted a hydrangea too although I pruned it and covered it with mulch in the fall which I'm now reading may have been a mistake?
There are some plants that were already here, some hostas that is like to divide and space out with the other 2 hostas and columbine I've planted this year, and a ton of nandina. I'd like to move to one oddball one but I don't want that to kill it.
I'd like to plant 4 more roses including the Tahitian sunset one I just got at springfest but I'm not sure where to put it. I'd like to do roses, another hydrangea, lavender, bleeding heart, hollyhocks, salvia, etc. but my budget is super small so over time. We are trying to dig up this area and mulch it, maybe put down stepping stones as a divergent path.
Also I have no idea what that little tree is with the white flowers

I figured out the tree is Photinia, there is three total but the one pictures is the most like a tree with bare trunk. The other two are on opposite ends of the house and are like giant 10 foot bushes. One of them has a wisteria grown in around it which annoys me every spring when it blooms, I would love to be able to do something better with that wisteria!

I found a bleeding heart and a columbine called leprechan's gold today, and attempted to dig up the nandina in the right side planter. I almost broke the shovel >.>

The roses I want to add the most are Blue Girl, Wedgwood, Koko Loko and a spring green colored one. I know they must exist because I've bought them as cut flowers at walmart neighborhood market of all places.

Get some better pictures of the large shrub, leaves, flowers, bark... and post in the ID forum. Lots of help over there in figuring out what it might be.

Here is your list with a few suggestions for plant placement.
Tall- back to mid-ground.
Short- in masses closer to the front, especially grouped around large rocks.
Shade- closer to the porch.
Sun- away from the porch, but watch out for hot reflected heat off the wall if it faces south or west. Some plants are OK with this, but some are not.

Here is how I would do this:
Draw the area to scale on a piece of graph paper. Use some tracing paper over it, or make several copies.
Get a circle template.
Draw circles about 75% of the mature size of the plant, locating each circle in the sun/shade/front/back where it will probably do best.
Overlap the circles just a little bit. Cottage gardens will look crowded, but don't over do it. Allow each plant its space, especially the first year. See what you like, what does well.
Then remove the stuff that did not work and get more of the things that are working, or try something else.

coral bells- Perennial for part sun/part shade. Tends to stay small, looks especially nice tucked into rocks.
hydrangea- large deciduous shrub for shade. Will handle a certain amount of sun as long as it is not hot reflected sun off a south or west facing wall.
hostas- Perennials for shade. Many varieties from about a foot to 3' high and wide. Tropical looking leaves.
columbine- Light and airy perennials for sun or bright shade. Not reflected heat. In a warmer summer location, more shade is better.
nandina- Evergreen shrubs varying from 1' dwarfs to 8' giants. Some spread more readily via underground runners, most form a reasonably well behaved clump. Showy leaves, small flowers, and fruit that attracts birds and may reseed.
roses- need a bit of room. Maximum sun. Check each variety for size and shape. Do not crowd with other plants, needs good air circulation to avoid various fungi.
lavender- Shrubby perennials that range from 1' to 4' high, and a bit wider. Full sun. Research the best varieties for your area. Lavandula angustifolia varieties tend to handle the cold better than most others.
bleeding heart- Perennial for forest floor, shade, moist...
hollyhocks- Tall annuals, biennials or perennials. Many varieties. Most of the common newer ones are annuals, and they have been breeding them smaller. The tall ones might need staking or something if you are in a windy area. Full sun.
salvia- MANY species and varieties from 1' to 6' high or wide. Some are low and spreading, some make tight, round clumps, some are giant bushes. Most are perennials, and even the somewhat shrubby ones are often cut back like perennials. Do enough research to know which ones grow in your area. The annual types can be grown through the summer in full sun. Some salvias come from very dry locations, so would not be compatible with the other plants on this list.