I'm currently researching local CPAs and attornies as well as the many many online incorporation/LLC building websites as well as just reading BP articles and forums.

What would be the best way to incorporate their investment into our current situation strategically and legally?

Try incorporating a game room or movie room and when you theme it don't just buy a Mickey comforter and frame and call it a day, really try to make each room unique (Star Wars room, Avengers room, Princess, Harry Potter etc) and go above and beyond.

I just want to incorporate be it trust or LLC so that my assets are protected.

I incorporated an LLC in Arkansas, and just finished opening an account remotely with Mercury Bank. 

The other thing I've heard is that the cleaning fee can be incorporated into CapEx, Repairs/Maintenance, Booking Fees (I typically run these all at 3%).

He lives downtown mortgage free, incorporating long term tenants, traveling nurses on month to month, and the occasional friend/family connection for a STR.

I'm nervous to do a big renovation but will need to incorporate creative financing in order to scale.Do you ever find sellers open to seller financing / sub2?

Covers the existing structure and the renovations as they are incorporated. 

I calculated these numbers last night...and actually when we put it under contract, we had a last minute bump in price by $10k that pushed the IRR up to 25.72% from the 25.49% shown in the graphic and for the calculations.