John, can you explain what you mean by "2 (a)"? The overgeneralizing/overlapping?
I know I've had this obstacle before, meaning #1 both (a) and ( - I marked your paragraphs and changed format a bit for easier reference. I did find that in those cases sometimes the idea was not meaty enough - and I was NOT interested in magnifying or adding on to it. Or, for some other reason while the idea was big enough, I couldn't amplify.
What did happen in one instance with such a lyric, was this: the original idea was that of a woman's pain and longing (which was absolutely palpable to me, after seeing a certain documentary). I wanted to tell her story. But I could not communicate what I felt. Somehow I ended up writing instead a completely different story and the only thing left of the original idea was "pain and longing".
Re: #3 - that's a toughie when combined w/ 1 & 2. I would advise keeping your edited solid lines. A couple options spring to mind. One being to consider yourself a storyteller (maybe you have already done this? I hadn't really, until Last Train). I found that took a lot of pressure off, to finish the idea. It is true, the lyric ended up going somewhere I hadn't intended, and maybe didn't even want, but the more I could consider myself more as reporting or as a detached sort of recorder, the more options opened up for me as to finishing the lyric. And I was able to quickly pare down those options, once they revealed themselves.
As far as getting caught in editing loop before the idea is down...either you have finished the idea (seriously) and need the beginning, middle, end to fatten it so the listener can glean SOME kind of completed picture - or it just stands alone, to be either put with some other gem verse someday, or not. That's my opinion anyway. Or - maybe putting it down for awhile, do something different and out of your routine and life, to help get you dreaming or whatever it's called, thinking in a different way, letting go somehow.
I fear this is no help at all ~ but Cheers anyway.
Donna