I've had a couple of trikes over the years, both pedalers. I've always wanted to motorize one, but the stars have not been in alignment.
If I were to do it today, I would go electric, but I'm stuck between deciding mid-drive or front-drive. I've ridden a FWD electric-hub trike and loved it. Batteries under the rear platform down low for best handling. If I _had_ to go gas, I would do front-drive for sure, because trike drivetrains are almost always permanent 1-leggers anyway, and FWD trikes seem more stable. RWD trikes with significant power have wonky handling characteristics on top of the already wonky trike handling.
Anyway, that's my musings on the subject. Welcome to you and your boo to the forum!