Based on the pictures you've provided, here's an approximation of how I think you could place trees in the yard. Two small trees must be at a distance from the face of the house, so they need to be across the walk and into the lawn area, with groundcover islands below. This way, serviceberry would work. Or dwarf burning bush. (Yes, it will take some time to get to size, but won't be a problem over the long haul.) Or it could be common lilac or anything about that size. If you want more detailed help, better pictures are necessary. You would take them from somewhere in the street while standing opposite the center of the house face. A series of 3 overlapping shots, pivoting from left to right would be needed. All 3 shots would need to be taken from same location. And, of course, you would need to move any car blocking the view.

I'll try to play catch up. (Have been travelling for a little more than a month in the past 40 days. Much of that was without Internet so more absent than I thought might happen.) The drawing is pretty basic but hopefully it will convey some ideas. First, I would get rid of the odd angles on the beds. They would look much better to tie in to walks at 90* angles instead of weird wedge shapes. In the lower, right corner I'm illustrating two ways you could make a circular bed around the lamp post. (The lamp post is a primary purpose of the bed so the bed ought to use the post, at least roughly, as the radius point. And a generally circular shape would make more sense than a sprawling asymmetrical wedge shape.) Also, I would re-shape the large front bed. It should swell out to accommodate the tree you intend to plant but does not need to extend outward, around the walk in a grabbing fashion. To explain the planting in the illustration, it is a shrub below each window of the garage, and a small hedge below the pair of windows (right half). None of those should get taller than bottom of the window. There is seasonal color flanking the entrance to the porch and at the left of the porch. A perennial mass wraps the garage corners and right house corner. A low groundcover, solid, links the other plantings together. Can't tell how your existing tree would possibly conflict with the proposed tree. (The third picture you posted was taken from a different position so the existing tree location shown could be seriously misleading.) You might want to consider moving the proposed tree farther back in the scene rather than placing it at a pure diagonal to the house corner. (I wouldn't know because we don't have the information.) A large shade tree is probably not in order. A flowering tree (such as redbud) might be a better size to use so close to the house. As far as what plants to use, gauge the heights and research what plants grow locally that could perform well.

I'll repeat what others have said about waiting a year before doing anything. You don't know what hasn't come up & what you like/don't like right now may change once you get settled in. You should go to your settings & include your zone & at least what state you are in to give others an idea. What works for me living in south Arkansas may not work for someone in Georgia. I personally do not like trees planted near enough to a house that in a few years the roots cause problems with the foundation & septic system (been there, done that). I do like shrubs like azaleas that are green all year & then pop with color in the summer. Do your big stuff first like trees & shrubs, then work the small plants like flowers around that. A local mom & pop nursery would appreciate the business & could give you a landscape planning overview, maybe give you a discount on your order if you buy from them. Before contacting anyone like that, go to your local library & check out the books they have on what grows in your area. Also visit nurseries in the area. You'll get an idea of what grows in your area. Go to your local county or parish (if you live in Louisiana) extension office. They'll have tons of information on everything you can think of for vegetable, flowers, ornamental grasses, etc. And everything is free. Write down everything you want, even if the odds are you won't get it. Make a trade list here on GW & on any other gardening sites or Facebook gardening groups you are a member of. You never know who will have something for trade or postage. I really like that pergola!!!! That looks like a great place for a barbeque grill & furniture for outside gatherings. The stepping stones - remember that if they're sunk into the ground you should probably be able to mow without bothering them. This may be your first home, it may be the only home you ever have so you'll want to make sure the regular maintenance you have to do isn't any harder than it has to be. As for a herb & vegetable garden, start small with the things you guys like to eat & just keep building as you can.

I think sprucing up your lawn quality will go MILES. I also like the post showing a corner tree, and nice edging/mulch. You have good bones to work with, just needs more TLC.