Flowering plants, maybe one small tree.

Assuming it is open to the ground on the bottom, any bagged raised bed soil will work. Ideally, you want well draining, mineral based garden soil (aka "dirt") with a small amount of compost or other organic matter added.

I hope it is a very small tree. Or one trained as an espalier.

This is a sample of what i got. Thanks @gardengal48

Is there any way to prevent roots from pushing against the brick wall in the back?

No. The wall itself is as effective a barrier as you'll get.

Lol. Guess i have to avoid any trees

No trees.

That bed is tiny and anything you plant there must love heat - the sun off the fence and concrete will roast tender plants.

Have you considered vines?

update oh boy

Impressive. What are the plants? Can I see a Mango??!!

Looks great! Not like most of the US right now;)