Could you line the drive area with brick to give it a clear definition?

I would build a low fence on the parking lot side. I think brick would be nice for where the giant shrubs are now. I like grade level edging. Nice looking house you have there.

If it's not my parking lot, I think I would want a fence.

A fence will keep gravel from being scattered into the yard.

Take the bushes out first so you can see the brick on your house. You might use brick to edge you garden beds around the house but I think brick along the drive might draw attention to something that should be utilitarian and not a design element. There are companies that do concrete edging, poured and molded in place with a machine. That would be an option but I think an edge of concrete pavers (those meant for heavy traffic would work). You can't skimp on laying them on a tamped stone bed of the right depth and securing them with edging strips. I would use a color close to the stone or concrete color or possibly pick up a little of the red tone of the brick with a very light red undertone.

Picture 1: The bushes are out! Picture 2: Should I get more limestone and continue all the way to the end of the house in a rectangle shape? (I cannot raise that area because of those basement windows. Picture 3: Measurements of the space. Thanks!

The rocks form a nice contrast with the grass. You might want to use bricks along the gravel driveway because they are flat and can help confine the gravel. The embedded stepping stones can be edged with a flat spade or edger.

Remember, any fence or edging will have to be "trimmed around" unless it is flat with the yard surface. I am the trimmer in our "lawn mowing venture" so I always try to think of ways to keep "trimming" at a minimum. No suggestions unless you want to cement (which is expensive) a narrow type sidewalk to keep the gravel from going into your lawn. Sidewalk cement could be level/even with your grass so mower will pass over it..