Agreed- get thee to the MSF course! It's a life saver.
Other than that- sounds to me like it never really seized, or you would have experienced a jerk and a skid. If it was HARD to turn over, it wasn't seized.
Fueling issues for sure- specifically, I'm guess not enough air. But who knows, could be timing too- I've seen the same thing happen (sooty plugs, stalling, hard starting) from timing.
Get a timing light and multi meter (you'll need both of those again) and beg, borrow, or buy a compression tester. Make sure you have compression, make sure your battery is good and charging, make sure the timing is set.
Also- I don't know much about the 350's, but most Hondas from that period make less charge than they use under about 3k rpm. Could be that if oh already had a weak battery the time idling to warm up ran it down even further. If you kept the revs low, you might have just plane old run down the battery. That would lead to a weak spark (sooty plugs) then no spark (stalling).
But- THAT IS ALL CONJECTURE. You'll know nothing until you get systematic. Listen to the folks here- they walked me through a top-end rebuild ten days after buying my first bike, and I'd never been in an engine before. You can do this. It'll take patience, but you'll learn a lot and you'll never be scared of an engine again.