Oh boy I can’t wait to tell my parents to go to fff8::ab298:42cab3:187daq::1 to get to their router.

Well you could accept the default generated one, or set it to fe80::1 manually. Don't most good routers now have a DNS server in? So you could make it router.local or something?

I think some even by default make a DNS entry call router.local or similar pointing to themselves. This isn't a real problem and if IPv6 were adopted fully, then all routers would likely come with something like this setup anyway.

shouldn’t fe80::1 always just work if IPv6 is enabled?
If you set the ip of the router to fe80::1 then anything directly connected should be fine to connect using that address.