I've been a 6mm fan for a long time. I started with the 243 then rechambered to 243ai then to 6mmai then built a 6-284. I still own one of each minus the 243ai.
The 6-284 is going to be the king of the hill (as far as what you've listed), better velocity, no fire forming & WAY better brass (Lapua). That being said, I feel the 6mmai is more efficient & will last longer. A better case design with a longer neck should be a good bit easier on the thoat than the shorter neck of the 284 case.
I built my AI & 284 on different sides of the spectrum. The AI is a lighter weight (#5 contour IIRC) with a laminate thumbhole & 12 twist bbl. Launching 85grainers @ over 3500fps is a lot of fun & somewhat messy
The 6-284 wears a very heavy (don't remember contour, MTU-ish) barrel & McMillan A-5 stock with a 8 twist bbl. 107's at 3400fps is equally impressive.
At 15lbs, this isn't a stalking rifle.
If this is going to be a dedicated coyote/deer rig, flip a coin on th 6mm's pick up an 1-8" tube & chamber accordingly, you can't really go wrong with either.
6mm all the way.