Was there meant to be a picture? Other than suggesting shape and position nobody can help you with plant choice until they know your geographical location.

Your heading wants a flower garden. Your post wants a lawn. Which do you want?

Chop the tree down.

Whatever is relevant to the problem needs to also be explained by pictures.

Oops, I thought I had included photos, here are a few...

I would have liked a lawn, BUT have given up the idea and I’m working to make a nice design for a mulch/tree/sand/rock garden.

To design any garden, you start with a base plan drawn to scale. It shows house footprint, drive, walks, fences, property line, hedges, etc.. Keep the drawing simple. Don't show anything that is subject to being moved, individual small plants, crosshatching or shading. Don't even draw tree canopies ... just the trunks. You can draw this on graph paper or plain paper if you have a T-square. Or you can draw it in Microsoft Paint. (If you turn on the gridlines, it is a scale of 1"= 10'. (Holding shift key allows you to draw a line that is horizontal, vertical, or at 45*.

For getting help here with "ideas," for whatever part of the yard you want to work on, you need to take pictures that show whole, complete scenes -- all from a single point of view. In other words. The camera will stay at one position and take a series of slightly overlapping shots that pan from far left to far right. Usually, you'll want to show a full 180* of the view. You would need to be lined up with the center of the view .... not at one end where you are seeing the scene at an angle. (You would see the ends of the scene at an angle, but since the pictures overlap slightly, they all fit together.)

Encourage native ground covers. I have creeping potentilla (cinquefoil) that is green and pretty in my lawn. I have a lot of violets. I have shade, deep shade, really deep, dry shade.

If you want just green, then go with bearberry. If you want to walk on it, then you might want to make sure your lawn has a shade mix of grass.

Pic#2 looks like maybe a too much shade issue. Pics #1 & 3 look like you have something under the soil, too close to the surface that's causing problems.

Hand drawn design of garden...

Photo from top...

Potential outcome...

Ideas

I'm going to be straight up honest. The inspiration pictures, if you blur your vision a little, are not structurally a whole lot different than a basic miniature golf scheme. They have that theme of crazy paths and objects at intervals. I would not have any clue how to help you with that, as it seems much more like someone's personal modern art project. To me, it looks like there's a lean toward contrivance and clutter. That direction is too foreign to me that I would be of any use in helping you get there.

But to help yourself, you need an accurate and to-scale base plan. And even you would need the pictures as I described above if you were going to work on your project at the kitchen table or somewhere other than directly in the yard. (It is not very useful to have the aerial shots from the upstairs window because none of the neighbors' backgrounds show in those pictures. And you would need to see that.)

On a side note, it looks like the hedge that spans the front property line is on its way to getting out of control. I'd determine what that's supposed to be and get it in shape soon, as it will only become more difficult as time passes.

Thank you for all your help.’
I have bought flowers and plants and will try to maintain my grass!

How does this look?

For myself, I'm not a fan of plants lining a walk. It makes the walk seem more confined, which is usually not an asset. Granted, if the plants are small they're less offensive and the larger they are, the worse it gets. Plus, all the plants here are creating lines in the landscape. I think it is more pleasing to have plants arranges as blocks/groups of like plants, instead of everything being linear. If they're going to be there, I'd rather see the plants installed as a groundcover along the fences, than along the walk. There could be a bed under the widow that contains these groundcovers or annuals.

I know it's not where you're trying to go but a general direction like this is less bothersome to me...

I must say, I've admired plants lining a walkway. It gives presence to the entry. I've seen hostas used.

I wouldn’t plant those right into the grass. How will you trim the grass?

"It gives presence to the entry." What does that mean? How would we recognize presence?

I am another person who dislikes plants lining a walkway. They narrow it visually, and if they grow larger than planned, there is the lovely prospect of damp plants brushing one’s ankles as one uses the walkway.

House looks lovely and not traditional, lines and urns look reminiscent of Versailles...

No picture.

Latest!
Thank you for all your help.