"Can I get this and this?"
Maybe so but it's a poor way of doing it. The correction they gave me was これとこれをください。But I couldn't do that because there weren't 2 これ to put together. The only correct way was with こちら of which there were 2 but they hadn't been introduced so I didn't know. Should have figured that out, but oh well.
um.. this one is hard to explain これ と これ is rather you are referring to object. something you can hold and touch.. walk in Panda express and point food, and say, I want this, that and this.. you can point as many items. (never use to refer to a person, for person, it is このひと、そのひと、あのひと
then こちら と こちら is used when 2 of you walk in the restaurant, then waiter will point two seats and tell you to sit down, this chair and another so, it is used for place and also for person.. .こちら様(sama)とそちら様とあちら様，this person (nearest) and this person (2nd in line) and that person.
こっち is more like indicate a place... こっちに来てください、please come here. あっちに行ってください。please go over there..
Also, こちら is politer than これ.