I will say, last time I tried it, you can edit your offense/defense stats any time. Little bit of a pain but until (if ever) multi-participant RPFight is implemented, I’d say it’s entirely reasonable that people could emote supporting someone in the fight or trying to hinder them and updates could be made to Offense/Defense or vulnerabilities taken.
The LLM seems to generate vulnerabilities based on your poses, so in theory if one of the fighters incorporated mentioning the hinderance in their pose when choosing to take a vulnerability, it would hopefully choose an appropriate one.