I generally don't enforce dress code and at worst I might just make a comment if it something egregious, but the phone issue is an important one in the classroom. If you say nothing the entire class will just be on their phones.
Well yeah, that’s just being a bad teacher. But I’m not going to blame other teachers for something I can enforce in my own room
Just make sure everybody's bags are tucked neatly under the table first in case you choke on said hotdog and end up tripping and/or vomiting on someone's bag.