I watched your video. I am confused why, after a couple good starts, you did not continue riding forward past the 1/2 or 1 1/2 revolutions. Was it your plan to only ride 1/2 or 1 1/2 revolutions? You seemed ready for longer distances.
Whether or not to put a hand on the saddle may be determined by the degree of stability between your butt and the seat. It is common for beginners to ride without significant weight in the seat, and that causes a loss of stability. Which can be remedied by putting a hand on the seat.
I like watching kids learn to unicycle. A couple boys in my neighborhood, when they learned to unicycle, they held the grab handle with one hand. No one told them to. They were just intuitive. They needed stability, and they used their hand to get it.
If you’re interested in proper foot placement for the second foot, learn the tire grab mount. It’ll force you to lean forward and look down in the direction of the second pedal. Don’t expect to get a good pedal position on the second pedal unless you are looking right at it. Also, bad second foot placement can happen while rushing the mount.
I you go back to a fence or crutch, you will be able to place both feet in the right position. This will not help you get the right position for your current mounting style, but it will let you know what good foot position feels like.
The only bad habits needing your concern right now are the ones that could cause a bad fall. Bad foot placement is concerning. A missed second pedal could cause a face plant. I believe one hand on the seat is inherently safer, because the hand can guide the unicycle either in front of or behind the rider…during a sketchy bailout.
But, if you’re thinking about avoiding bad habits as a way to maintain some kind of idealized, pristine learning process, then I’d say unicycling doesn’t work that way.
Dude, go for it!