Re: > inability to object (and thus later integrate) to ones proposal
I've come across it rarely, but adding a new agenda item seems like the best pathway given what you shared. There is nothing wrong with modifying newly created governance, the only question may be whether the proposed change is based on a tension (see the criteria for a valid proposal), but usually it's fine.
FWIW - one question to ask the proposer, "Would it still solve your tension to have this accountability added to the original role?" Because if the proposal does NOT solve the tension, then the proposer could actually raise an NVGO objection (based on the reason that, by definition, a proposal needs to resolve a tension and this proposal doesn't). Additionally, it sounds like the objection might have been based on a misunderstanding about person vs. role, rather than because they were trying to help another role, but perhaps not.