Idle hang:
You need to remember what you know about harleys and apply it to this bike. Who has a leak from the spigot holding the carb, to the intake orings between head and Y-tie that distributes air/fuel only thru that passage. Can't be electronic is the advance curve. Sounds more like an air leak hanging up the idle. Sounds like a slide hanging up-check; sounds like cable hang-check again; sounds like a leaking choke lever-if applies... but if that was the case, rich to no start it flooded out with that kind of leak happening.
I'll forgo ign. Why? Not hard to start, not popping, no mention of say an ignition would be involved, or more like air leaks or mechanical at the carb instead.
Clutch Plate Lock:
Sure sounds like it as mentioned more than once. I did this, I did that, and for a ride down the road it was fine. Then it locked up again, I did not swap plates all around, so I should expect the same situation. I should be able to remove my derby cover, pull the clutch lever in with one hand, then move the clutch inner with my other hand.
I should be able to stab 1st with a dead engine, aim the bike in a safe direction, hit the starter button and two possible things should occur. 1) I start moving as the starter pushes me forward and now starts up and I go with clutch lever still pulled in. 2) I start the bike, the starter breaks the plates from the clutch outer, I sit there with a little bump forward before the clutch plates break and I sit and idle in 1st gear, clutch in, no popping out of gear, etc.