RE: 2nd Board
OK, of the boards you've put on your "short list" it's going to be a little hard to determine which suits your needs the best.
If you had a little less chop (I've seen the photos of the lake on big days) the Isonic 111 would be good, and if you stayed in more flat water (Wolf Lake) etc. it would be great, but out in the big lake in onshore/sideshore conditions, I'd take it off the list as being a little more "flatwater" oriented than what it sounds like you want.
Any of the other 3 would be very good.
Actually, for the big chop and for semi wavesailing or big freestyle moves, I'd put the Kombat Aero at the top of the list, but a 107, not the 117 which is a little big for the conditions you describe.
The 117 will work, but once the winds get to around 18 knots, it's going to start feeling big, very quickly.
Actually the Kombat Aero 97 would be even better, but I don't think your feel you can go quite that small at your skill level.
The S-Type would be a little faster, and works pretty well for freestyle and choppy conditions, but it's a little to "directional" for the conditions you describe.
The Carve 111 would also be a good choice, but it's not quite as turny as the Kombat Aero.
Hope this helps,