One of the first suggestions I have is to talk to an animal behaviorist (the phone is fine) at your local shelter. They usually have some good ideas that even we don't think of. How old is your cat? How long have you had him? What's he hissing at? Simone (my female cat) we're guessing wasn't socialized properly as a kitten and now has fear aggression. I talked to a behaviorist and she gave us some suggestions on what to do. Things we didn't even think of. Simone hisses at mainly women and we need to break her of that habit. There are some other behaviors were trying to change as well. So, maybe give them a call and see what they suggest to break the behaviors.
I don't know if this will do any good, but there is a thing called Feliway...it's supposed to help calm a cat down when there might be a stressful situation. I don't know that this would help your situation. Feliway is sold as a spray and also as a plug-in that only cats can smell.
When we first got Snowball he wouldn't share with Simone. He always pushed her out of the way when I'd feed them. I started filling her bowl first and would just make him wait and fill his bowl 2nd. Now he's to the point where he will sit and wait til you fill his bowl without shoving her out of the way. Maybe you need to feed your cat separately from the rest. Maybe make up food bowls in a few different areas so he can't be at all of them at once.
As far as the litter, did you recently switch and he doesn't like it? Is it maybe too dirty for his liking? How often do you scoop it? Maybe scooping more often will help. Maybe try getting his attention when you notice him start to tip it and get him interested in something else. I don't know what else you can do, cause if you scold him or squirt him with water he might associate the litter pan as bad and not use it at all.
I don't know that this would help, but it could be a possibility if you just recently got him. Someone I know was telling me she has a cat that will not poop and pee in the same pan. One pan is for peeing and one pan is for pooping. With multiple cats this could be a problem, but is it possible this is why he's tipping the pan?
Another thing to keep in mind, working with a cat is a lot like working with a 2 year old kid. How you treat them will determine how they react to you a lot of times.
Keep us posted what happens with your kitty. Good luck!