I suggest doing #1 and #2 in parallel.

As you said, the story is mostly done and just needs editing. That will require help from other people and can happen while you do other things. It will be good for you to be able to say "Behold, I have finished this thing."

At the same time, as you tackle the full story as a separate thing, it may be worth giving it your best effort (by pulling in #2) so that after a few months, you can say "I tried really hard and it didn't work. Alas. Time to stop." or the opposite, without having to wonder if you just didn't try hard enough.