you know what I meqan. one attempts to copy alis style, eg jabbing and moving the odd 1-2, the otghr bobs, weaves and tries to corner the other lots of hooks and uppercuts etc
Used to do some where each fighter is assigned a certain hand to punch with/ or a particular set of punches. (One might only have the jab while the other might have a cross and a hook) Lets you work things you normally wouldn't and find new openings with punches your not as comfortable with. There was always ping pong as well.(You throw a 3 punch combo and they counter with the same one). Also my coach used to tie two people together with a handwrap with about 3feet of leeway to make sure the fighters would work inside punches only. Pretty effective drill, gets you to rely on headmovement a lot more.
for infighting you can also take an old medium sized truck tire (little trailer tire for kids) and have them place their front foot inside the tire while it lies on the ground. they can only move back and forth a few inches and circles have to be tight, corner cutting angles. you can also use the tire with one person's back foot inside of it and they get to practice "holding the center of the ring" while the other "boxes" in circles around them. like with all drills it's wise to start with low volume and intensity and gradually increase accordingly.
Good idea :good. another thing we do, to Help upper Body movement, is put knee pads on, and lightly Spar on the Knees, really helps with Balance and Posture. Plus you have to be qiuck with the shift of the Knees, good fun.