Congrats on a huge accomplishment! Don't know what to say on the Skinny Popcorn. I do know from watching, that the people who tend to maintain their original losses are very strict with themselves. But I also know, that for me personally, saying I won't ever have something again or will never be a "weensy bit bad" is not practical. It's pretty magical thinking IMHO.
So I'd tend to look at your popcorn fettish like this: if you can eat your serving appropriate size and it doesn't hurt the new anatomy, cause weight gain/stall, or cause cravings to get out of control, and you can dictate the frequency of eating it--then no problemo. If on the other hand, it causes the binge monster to visit, makes you stall or gain, and you end up wanting more and more and more of it at increasingly shorter intervals--then it's a trigger food and should be avoided at this time.
I'm gonna shoot for a 95/5 plan where 95% of the time I eat like a saint. The other 5% of the time, I will enjoy like a sinner. And I will have a safety window. At the high end=angelic behavior; at the low end=devil behavior.