Several ?s concerning inside grow:)

In addition to my grow I plan on growing in a friends closet which contains a small attic space that is closed off by a small door. The problem is that the ceiling slants down inside the space, and it's only 3 feet tall and it's highest point.

What kind of strain should I be looking for that will stay small? Does a scrog type of grow reduce height?

Also, I realize in attic spaces the temp usually is about 20 degrees hotter/colder than the outside. Right now in Ohio it's fine, but in the summer it's going to be extremely hot in the space even without the lights. We planned on putting a window airconditioner inside the space, with the ass end of it hanging out a pre-cut hole in the door leading into the space, what do you think?

Indica plants generally grow shorter than sativa plants, if that helps.