(Regarding the Dan Slott and reality designations thing) In ASM#9, Dan Slott stated the reality of Spider-Gwen was Earth-65, the Marvel Appendix site (the one listed in the final page of the OHTMU Vol 5 as where to check for updates in reality designations) had already listed it as Earth-14211. When asked about it via Twitter, he answered that unless mentioned in comics, reality designations from the Handbooks (that would include every OHTMU in paper form) do not count. I hope that's enough info
Given that Spider-Gwen is a new character, I find it difficult to imagine that the Handbook guys would have a designation in print for her world so quickly. So there’s something else going on here–that may be the world of some other alternate Gwen, for example.
At the end of the day, though, information in teh stories can trump information created for teh Handbooks.