The furthest I ever got was creating firewall rules for ipv6 that mostly corresponded to our ipv4 rules. These were never used, but they were tested and ready. This was around "ipv6 day" (2014? 2015?) I've thought about it on and off since then and wondered whether I should be doing more with ipv6, but haven't actually taken any action in that direction.

I wonder if there's a relatively simple solution to at least most of the OPs list, all having to do with outgoing ipv6 requests, which would be proxying such (or all) requests through another computer on the network that has both ipv4 and ipv6 interfaces. Maybe that is an oversimplification.

Anyway, ipv4 definitely has a problem, and something is going to have to be done eventually.

Edit regarding World IPv6 day. I must be thinking of June 6, 2012: "This time, it's for real."