I'd say a guaranteed way to keep a tree shorter is for it to repeatedly freeze to the snowline during test winters.

I'd go with Antonovka; you can keep it short, but spreading. It is absolutely bomb proof.

I don't believe -25 threatens any common apple rootstock. Aren't those root stocks required only in z4 and lower and where hardy apple varieties are also required?

Not much help having hardy rootstocks if the scion dies.

Both rootstocks could make a tree taller than advertised. Keeping things manageable is more about pruning than anything else. I think either one would be fine, the antonovka has the advantage of being grown from seed and so you have more genetic diversity than the cloned Bud 118s will have.