The only mini drift boats that I know of are wood boats made by Greg Tatman. gregboats.com or Don Hill. dhdriftboats.com
please JD no direct promotional hyperlinks to non-sponsors!
I have seen some that resemble the od rapid robert, a square end boat that kind of resembles a pram.
Here is my take on small db vs pontoon. Anything small enough to fit in the back of a pu is not going to have a lot of room. Basically you, whatever gear you can carry on your back, one, maybe two rods, and a small dog.
Two guys, it's gonna get real tight.
A hard boat will track & maneuver better due to the hard chines. But an inflatable will bounce off a rock. If it were me, I would not be tearing down an inflatable after each use. Pain in the butt. I would figure out a way around that. Trailers good enough for an inflatable are cheap. Everything on an inflatable must be lashed down. And figure on gettinig wet.
Everything is a trade off. The best advice I can give concerning inflatables is, get a good one. Not something held together by hair pin clips. Keep asking questions. Try and keep an open mind and listen to everyone who has or has had a boat,,,of any kind.