The reason for only liquids immediately after surgery is to give your pouch/stomach a chance to heal. The last thing you want is to push the limit and blow out your staples or stiches. That's the reason why after a period of time you transition to purees, soft foods, then back to normal type of eating.
Actually, you'll want to be careful throughout your whole journey so you don't continuously overeat and stretch your pouch back out (it happens naturally, but it can also happen faster/bigger by pushing it).
Yes, you will be able to take larger drinks (try not to gulp) within a reasonable period of time. Just listen to your pouch (as it's your new tool and WILL remind YOU when you're pushing it) so you don't get sick.
Good luck! Always here for questions!