Any or all are good. Except for some exceptional 40lbs, bear are not exceptionally tenacious, but they have long fur, clot very well. I clean shot through a smallish bear with a 300WM in 96. He only ran 75 yards, but left not 1 drop of blood except where he was hit. You really want to either anchor them or at least guarantee a double hole for tracking.
I disagree a 30-30 is way more powerful than a 44. That is not a really qualified response as the two are deigned for different design paramaters. The 44 with hardcasts will outclass the 30-30 any day of the week in pure penetration and tissue damage at 50 yard bait distances, especially out of a carbine. The 30-30 will outshoot the 44 out at 150 with good bullets, but most people I know that us the 30-30 rarely use good bullets (7.99 walmart SP specials are the norm).
Get that 45-70 goin so you can bring a real gun hunting. Try some leverloution. I had good results in the marlin. If you can keep 2" at 50-75 yards, that's all you need. The Winchestr 300gr with noslers are good as well. They will clean shoot through most black bear.