Interest rates aren't likely to go up fast enough to worry about being locked into a 3 year (or 5 year with a corresponding 3-5% rate increase) term, in my opinion.
The borrower not paying is what we all try to minimize, it is clearly your primary risk factor. Some hope for remedy, some sell at any sign of trouble. Devise your own strategy.
Borrower paying off early is a hit, but a small one. If they pay in full in month one you'll probably lose a few cents to fees. I had a D4 pay in full in month two, I still made $0.52 after fees, or 2.08% over two (perhaps as much as three including funding, approval, and payment processing) months. It may not be what you were planning on, but I'll take that happening 10 times over a single missed payment.
According to the documents on their website, there is a successorship arranged that would provide for continued loan servicing and payments to investors. I do not know if that information can be independently verified, but I have no reason to doubt its validity. I don't know what would happen to undeployed cash and whether more of the borrowers would default with a different collection team, though.
The risk I take note of that you didn't mention is liquidity. Notes can be sold, but if you want to keep your shirt you will need a period of time to sell them and get your cash, should you need it.