A 16, the right 16, would be absolutely fine. I just have a nice one in a hammer gun, so it would have to be a hammerless for variety. Certainly, I could see that working.
Doolittle is exactly 1 mile south of me. I never hunt there as I have more birds in my front yard than that place, but I'm not aware of if being a nontox site. The places I do hunt are not, and I don't think they are likely to change.
In looking at Gunbroker, and using just Sterlingworth as a search item, I find a whole bunch of nice guns. Many would be excellent, but more than I have in the way of $ at the moment. I think that tells me I need to save up a bit, and not buy cheap or I'll regret it.
2.75 chambers would be preferable over 2.5s certainly, but I suspect I really don't need 3". The thing I like about the 3" however (and to the extent that I know what I'm talking about with 20s, which I don't), is that they would have ample room for blackpowder loads and wads which seem to be so much more space constrained that smokeless. I would be just fine if I found a gun that I would only load with black. Smokeless would be convenient, more for shooting at the range, than for hunting.
I'm not too worried about bears either. At least not here
