Why would you haft to make it a puller? You do not need the cover to keep the engine cool. I have made all my airboats pushers like real airboats and do not have cooling problems.
I run Gas not Nitro as far as a Prop adapter I just finished one with Left Hand threads 8Mx1.25MM for a customer with a chain saw engine for his Airboat. This Prop adapter for your boat needs to be right for safety reasons I have seen on this forum and others Prop adapter made out of plastic and other rigs to hold on a prop the RPMs are to high for that kind of stuff.
You will need a make Good engine stand and some runner’s glass in the bottom of the boat to attach the engine stand too.
I will stop here before I step on someone’s toes.