Tire swings will definitely help with core endurance.
Your hands will eventually get stronger, so this problem should be gone in no time and you probably cannot make a fist because of either poor hand...
I really don't know of any shorter fighters that like to move laterally and actually box instead of brawling. I would imagine for shorter fighters...
chewing gum is something i believe will strengthen your jaws.
Do some ab workouts
Amir Ghaffari Nikou
1. Vinny Paz 2. Andre Ward 3. Marvin Hagler :happy