Kind of tough to answer unless you tell us what you are going to use the rifle for.
But since you didn' t get any other input I will take a poke at it.

.270 is a good choice for a deer bear antelope rifle, can be stretched to use for elk. It is a long action cartridge.

The Remington Mtn Rifle is as good a choice as any. Do you like it, that is what matters.

I always buy Leupolds vari x III because of the eye relief and they just always work, they are a little more money than most scopes but I hunt a lot.

If you don' t hunt a lot you may not want to spend that much on a scope. I can' t speak from experience on any other scope brands.

As far as magnification, again it depends on what you are going to use it for.
Generally a 3x9 or 2.5x10 is a pretty good choice. Just try to find one with at least 3 1/2" of eye relief.