Good to know. I've never been asked what round I'm hunting with, but wasn't sure how explaining it would go if needed. Simply showing it's a 'big' bullet not a 223 would probably be enough, just want to be on the safe side.
Unless Winchester can convince some midwest states to alter their regulations to allow 0.355 instead of 0.357 I don't think it will be here for more than a couple years. I do like the numbers on the 450BM, and it sounds very effective from all I've read. May still end up going that route, not sure yet.
A lever gun in 444 or 45-70 would be nice, but a good condition pre-safety JM rifle and ammo for it would both be a bit expensive. Can 45 Colt make 1200 ft-lbs? Never looked into it because I didn't think it'd meet the energy requirement.
Yes. Buffalo Bore has a couple of loads that meet the spec.