I'm using IRV as a shorthand for ANY of the instant runoff voting (ranked voting) systems.

I happen to prefer (Path Vote) https://en.wikipedia.org/wiki/Schulze_method as a method of performing an election with instant runoffs for one round of ranked ballots.

For the later proposal (where districts are replaced by a mixed bag of candidates and issues) https://en.wikipedia.org/wiki/Schulze_STV might be a good way of determining the membership of a body.

It looks like research into proportional voter representation is still ongoing, with important new papers released even this year.

Glad to hear! I think RCV is the more general term, but the IRV people have worked to try to make it synonymous with IRV.