Welcome to the forums.
3. Make Halsin another male companion (I mean, that's a hot druid, like I want that. It's a personal asking
He he. I find Astarion hotter, but to each their tastes. But, yeah, Halsin is cool, and in my top 3 people I want to become (non-Origins) Companions, with Alfira and Minthara.
5. Would love to know what to do with all the keys I found.
There's a thread about this at the moment. Dropping a +1 there may help (or not, I don't know, but I doubt it would hurt).
6. I love all the books and lore and secret missions that accompany some of them.
The attention given to little story details is one of the great strengths of this game.
9. Would love more backgrounds and if they played within the dialogues (It's fine if they don't)
I love the idea. Though it might possibly be better to just keep the 13 standard background, but give more flexibility and roleplay opportunities within each (notably dialogue options), and let them be interpreted in a really wide way. For instance, a Guild Artisan could be a merchant, a Sailor could be a Pirate, etc.
I do feel bad for making suggestions and I don't know why, I think maybe it's because I know how much work and effort went into the game and asking for more or something different just seems selfish.....
The point of EA is for players to give feedback. Whether it's existing things that don't work, things players hate, things players love, additions players would love to see. Larian needs to know what players want. What they do with that knowledge is another topic, but we should certainly make suggestions and requests.