Those NelLusso's look really cool. Congrats on the build! I like how the rear rack is "already there"... it looks pretty beefy and as an added bonus, it strengthens the rear frame. Win-Win. Due to "The Great Big-Box Bike Shortage of 2020", I had to jump on the first red Cranbrook that showed up at the local Wally.
This will be a differing opinion than most, but the Predator 212 (stock) is a very smooth refined source of reliable power compared to, say, a 5hp B/S flathead. Almost every cart, bike, scooter, etc that I've converted to the Harbor Freight 6.5 has improved in reliability, smoothness and power. It's like the Cadillac of project engines. I think as long as anyone dots their I's and crosses their T's on their builds, should do fine with the Predator 212. Since the NelLusso and Cranny are almost the same, it does SEEM possible to fit a 212, but with some surgery. I'm going to target the seat post tube area, to avoid messing with the lower frame tube, which seems to me to be more of a "load bearing" part of the frame.
I can't wait to see which direction you go on the NelLusso build.