Are all crab apples edible?

[Chicken Run]

I am looking at buying a crab apples tree for decorative purposes. Its going against a 5ft wall in the garden.

Firstly are all crab apples edible as I have 2 children?

Secondly how tall fo they grow and will I be able to keep it at a height of around 6ft?

Its a Malus Gorgeous.

They have a full height of 6m but can you restrict the growth?

[PAULW]

They will be edible but probably as sour as lemons which will stop the kids eating to many.

[Flummery]

But brilliant to preserve with so great for jellies. I also use the strained, cooked juice (as if I were making a jelly) in with other ingredient to make chutneys. My Crab apple and Damson won a first place in our village show. It's a fabulous ingredient.
I would think you could prune it if you want to restrict its height. You can prune other apple trees, after all.