Having trouble getting my account back and some other questions

Hello all,

I played GW2 back at launch for a while with a friend, and after he quit I ended up quitting as well. I'm considering getting back into it with some friends who want to try it out, and have a few questions.

1. I was trying to recover my account, as I do not remember the password but when I entered my info it asked me for a serial key and a name of a character on the account. I have the serial key but I don't remember any of the character names I had since its been a few years now....is there any way around this? I had some good stuff on that account plus I got it when the game was still $60 (looks like the base game is free now) so there is some attachment there....is there any way around this?

2. Looks like the game is still active from what I can tell (at least looking at this subreddit), but do I need to purchase the latest expansion to do any of the end game stuff or am I ok for now (mostly asking because my friends like F2P MMOs like Tera, so I don't want to make them buy stuff if they don't need to). I do not know how far we can get on just the base game (as I see the level cap is 80 but maybe only if you have HoT?) so would like to double check that before jumping in.

Thanks all!