What a fun example! That's exactly the sort of stuff I use multiple cursors/regex for. Due to a bit of luck (the refs only appear once, and only appear in order of mention), that specific example ends up being quite a bit easier and faster with multiple cursors (and I believe his example also relies on that). For the more general case, multiple cursors wouldn't cut it though, so I'd have to jump out and use code. And multiple cursors definitely wouldn't scale to multiple docs!

For fun, I did that same example with multiple cursors + vs code: https://www.youtube.com/watch?v=H1uvNbtqJGk