If you can find a demo of the new LL Stomper 80, try that one too. Wouldn't be as edgy as a Burn; sounds like another great whitewater boat.
I am surprised that a Remix XP 9 is listed as only 73 gallons; it should have more volume than a medium Burn. Sounds like a typo to me. The Remix XP10 is 105 gallons; those XPs are bigger boats; should have plenty of room for touring.
If you want to do more lakes and touring, and a little class II-III whitewater, an XP9 could be a good way to go. But it will be harder to turn in boulder gardens, creeks, etc. If you want to get more into whitewater, a Remix 69, Stomper 80, maybe an M Karnali or Shiva would be good boats to learn in. Try some eddy turns with all of them to compare. Demo all you can.