Some Suggestions

[Enkidoh]

As far as I know, name changes are planned for the future, but don't quote me on that. But SE did confirm that the upcoming marriage system at least characters are free to marry regardless of sex or race (my bf also plays a girl miqo'te too so this was something I've been worried about too). So same-sex character marriages will be definitely possible.

You can't accept quests or speak to npcs while mounted at the moment sadly - it's something that's been requested constantly but so far there is nothing known about whether SE will allows this later on.

As for PvP, at the moment it's 8x8 battles against two parties essentially. From what I understand the new 'Frontlines' PvP system planned for the future features a 'capture-the-flag' type scenario, so if that's the case, you won't have long to wait.

Hopefully this has helped answer your questions.