Hi, I'll answer the bits I can answer from the top of my head, I'll look into the rest later.
But as WiFi is mentioned nowhere, this looks like wishful thinking to me.
Policy shouldn't mention specific technologies at all. Policy should be generic enough to allow for variations and future developments.
Let's play it through: The policy change gets approved and implemented, and now a /64 of my IPv6 PI for my WiFi is ok. (And giving a /64 or less to my kids/neighbour/barber is as well?) But, I actually operate two WiFis, one for the general public and one for my family. Thus, I now use a /63 in total, but only a /64 each, for WiFi. Ok, not ok?Ok, as: »Within the context of these policies, a sub-assignment is an assignment of a length of /64 or shorter.«
(Actually, it would not be ok, as »/64 or shorter« still prohibts use of /64 for e. g. WiFi. The proposal therefore should read »/63 or shorter« or »shorter than /64«, I think, or SLAAC is not an option anymore.)
You are misunderstanding. We're not talking about what you configure on your Wi-Fi, we're talking about what you delegate to third parties: the users of the Wi-Fi. Unless you assign a whole /64 to a single Wi-Fi user it's within the proposed policy. Cheers, Sander