"OTOH, if someone had been home at the entered cabin and held him off at gunpoint and he died, would that be considered manslaughter?"

Where I live, the standard has always been: what would a reasonable person do? In other words, would a reasonable person be in fear for their lives/property? If "Joe" knocked on my door asking for help and I remained silent, and then shot him when he broke in, I might be charged since a prosecutor could logically argue that I acted unreasonably. But if "Joe" broke a window and crawled through without warning then the shooting could be ruled justifiable and I would probably not be charged.

Lots of "mights" and "probablys" and "coulds". Like I said, the prosecutor has a great deal of latitude--and you just never know what a jury will do.

Vince