Regarding the "potty" situation, I agree with what hcarey had to say on the subject. It takes a fair amount of attention but when Sage was younger, I would always try to gauge time and body language and get her to one of two perches and tell her "go potty" until she did followed by praise.
Over time I stopped trying to time it but would just regularly take her to a perch and say "go potty". If she needed to, she would but if she didn't she would crouch down and pull her wings back to show me she as trying but nothing was coming out...
She is still pretty good about it but I have to admit that as time passed I have become more lazy and tolerant. I have a chair cover and always wear "bird shirts" when she is on me. Even so, she generally will fly to her stand when nature calls but there are occasional mistakes.