I have talked to a couple of pretty savvy aviation attorneys regarding the use of an LLC to protect me when flight instructing. Their response is that in a sole proprietorship LLC, it would take any decent attorney about five minutes to penetrate that veil, and get to YOUR personal assets. I got similar advice from an insurance broker, who I wasn't insured with, and who wasn't offering me insurance. I opted not to form an LLC on that advice.
I too would be VERY reluctant to lease out an airplane, especially one on floats, unless it was to something like an air taxi business, with VERY high pilot qualification requirements. I can introduce you to a couple of fellows who've been down this road, and lost their airplanes. Got reimbursed, but not without a big fight, and legal fees.
If you do decide to lease the plane out, make ABSOLUTELY certain that you write up and have the leasee sign a VERY restrictive contract, which requires LOTS of insurance (I wouldn't even consider ANY deal like this without $1 million SMOOTH, plus full hull coverage) LOTS of PIC experience, a THOROUGH (as in 20 to 25 hour) checkout in the plane, etc. I wouldn't even consider leasing to ANYone with less than 500 PIC in seaplanes.
If they're not willing to go for that, I'd forget it. You'll be better off to pickle the engine and park it on the bank for the summer, and money ahead.
There are LOTS of folks out there who will happily wreck that airplane for you, then walk away, and leave you holding the bag. The $1 Million SMOOTH insurance coverage will HELP to protect YOU, since it's likely that the insurance will actually cover everyone who might be injured in an accident.
MTV