- Only one ship ever got a letter suffix added to it's hull number and that was Enterprise.
- the "arrowhead" was always the overall insignia for Starfleet. the other insignia seen in TMP we not emblems for specific ships, but for sub-sommands of the fleet. Enterprise folks wore the arrowhead because they were working directly for Fleet command.
That is also part of my personal continuity. Also, Klingons have always had ridges and I ignore the episode that tried to explain it.
I actually ignore the entire Enterprise series.
I see the entire Star Trek Franchise as fictional so I don't mind when our history doesn't line up with theirs. I am pretty sure we will not be visited by Vulcans on April 5, 2063.
I see JJ's Star Trek movies as existing in a parallel universe all on its own and Spock and Nero were from the future of THAT universe and not the original time line at all.