When writing novelettes,

I'm having a little trouble connecting your first paragraph with the rest of your post, so sorry if I'm totally misunderstanding you. But I don't think characters need to have a wide range of interests to feel fully dimensional; it's more of their reactions to the presented set of events (however many you fit in to whatever length the story is) that make up their personality for me. It's totally fair, in shorter works, for characters to be pretty focused on the plot. And their backstory should show up in other ways, whether via explicit flashbacks or just little bits of background details inserted into observations.

One suggestion that may or may not be helpful is that if you start the story from a point when things change, presumably there's a previous situation in the setup that could exhibit some other aspect of the character pre-plot-craziness.

It really depends on the details, but I don't see any reason why your characters couldn't have diverse interests, so long as, for the moment, whatever makes them interested in the plot is the most important thing. You could have one character have to cancel their regular poker nights because of the plot, or the _____ that another character had really been looking forward to that he can do only once a year or something, or other small things like that. Those just have to be mentions, a sentence or two each would cover it because. The most important thing in a short story (and really in any story), isn't as much that the characters are fully flushed out and we see all the aspects in their lives, but rather that the reader can get the sense that those lives could be flushed out.

Maybe more important is to convey why each person cares about the plot? Is one just intellectually curious, while the other has a vendetta, or maybe their recurring poker game just got ruined by the plot.

Does the old story still interest you?

Unless you are really jazzed about it and love the characters, love this story's depth, I would suggest writing a new story instead of re-hashing an old piece of work. I think we learn something new from every story. I think it's most difficult to think small and let go. When we get that feeling of having to round everything out, fill every hole, touch all our bases, the story, in my experience, becomes bloated and unwieldy. Since this is in the short fiction section, I'm going to give short fiction advice: novellettes and novels-- such a commitment!-- write a new character, a new story, a new idea. Finish it. Learn how to make it work, make it entertaining. Write the next one. Rinse, repeat, have fun. Hope this helps.
G

I must be missing something. I've written a bunch of novelettes, but I have ni idea what it is you;re wanting to do, or what the trouble is? I may be failing to understand because I don't think I've ever had to deal with plot holes.

But I also don't add subplots just for the sake of having a subplot. I believe a subplot should be an integral part of the story, a natural outgrowth of character that springs up simply because the characters are human, and have problems outside the main comnflict.

Story and subplot don't have to flow together because they're one and the same.

For me, it's one heck of a lot easier to write a good, coherent story where all the parts flow when writing at novelette length than at short story length. I tell the same story in both lengths, but the novelette just gives me more room to make the story wider. I can add detail to the novelette story that has to be left out of the short story.

But as I said, I'm not sure I understand your problem.