Don't have any experience with any of the cold steel products, but I think I'd go with the smaller of the two Bushmans. At least, that's the one I plan on buying in the future sometime. It would be a backup to a backup and would double as a spear point, so I wouldn't be carrying any important gear in the handle. Heck, I wouldn't anyways cause you lose your knife, you lose your gear too. I think I'd probably try wrapping the handle with some paracord though.
The tomahawk might be a bit light for serious chopping but it should get some of the smaller jobs done as long as you don't whack the handle to often like I did on one, lol. If you get one, let us know how the balance is on it. They are a lot of fun to throw, especially if you can actually hit something with them, lol.
As for adding a SAK to your kit? ABSOLUTELY!!!! As long as it's a good one like a Victorinox or Wenger and my preference would be that it had a good wood saw on it. We have a few, but none with a woodsaw and I can think of quite a few minor chores where it would come in handy, so I'm opting to suppliment with a German military issue utility knife.