That looks like a pretty straightforward way to add an electric motor to a kayak. I will be curious to see an update after you have using it for a while. The short video of you running it looked good. I guess your thinking is use it like the big motor on a bass boat. You will certainly be leaving me in your wake if I see you out there :)
Pretty nice motor Tom. You should reach out to Wilderside Gear about their freedom launcher wheels. Tell him I sent you and maybe you could work out a deal for a video with him.
That's a good question. I would look for something that you could easily mount an electric motor. Give me stability, Bonafide possibly. I would just look around. There's a lot of good deal on the used market right now I would differently check those ads out.