So I'm playing BG1 for the first time, met the dude, asked him about his hamster and called him a looney. He didn't like it so I had to kill him.

Does the whole BG community hate me now? :O

What happens in BG2? I faintly remember that in the very first dungeon you got him as a companion. When you import your character/save, will he not be there? I also never finished, nor actually played past the first hour of BG2 and am planning to do so after I finish the first one so I'm curious about what happens.

If you're playing vanilla, then importing your PC to BG2 won't affect any other characters.

If you're playing with BGT mod, then character stats/levels from players who were in your party at the end of BG1 carry over.
SOME characters who died in BG1, will be missing from BG2 (with BGT mod), but some (like Imoen, Jaheira+Minsc) show up anyway (unless something changed in a later version than I played). Some of them are too integrated into quest-lines for it to be any other way.

I'm playing the EE version with no mods.

Minsc will be there, as will Jaheira, Viconia and Edwin. Coran, Safana, Faldorn, Garrick, Quayle, Xzar/Montaron all have cameo appearances. You could kill every one of them in BG1, but they will still show up.

Death is only a minor inconvenience for the likes of Edwin

@OP: I also killed Minsc on my first playthrough :D
Didn't find out until later that he actually was a potential party member (also, didn't have an internet connection back in '98; so I had to hear it from a friend who also played the game)

How could you do that! Dont you have any good in you!

:))

Joking aside, i guess others answered your questions. Minsc is celebrity in Baldur's Gate world and for good reasons. He is funny and an excellent companion for any good aligned party.

Well, in Baldur's Gate 2, I killed Imoen before leaving the starting dungeon and she still showed up in the cutscene upon leaving it.

By killed, I actually mean killed; I did not simply trigger her "leave the party at 1HP script". Of note, her belt makes her immune to death from HP damage as well as many other things, so I had to use a combination of Contagion and a Scroll of Weakness to do the job.

(Anyone ever use Contagion seriously? It seems like the sort of spell that is useless for normal play, and only good for playing around like this, and only because it stacks with itself.)

(Note: The Enhanced Edition may work differently in some respects, so what I say might not apply there.)

You had a dialog without saving first and trying out all dialog branches for the best possible outcome via reload spam ??? You didn't even print out a walkthrough before playing ???
That's dangerous, it's safer to have someone else do the game for you and watch a let's play. ;-)

Lawful evil, man. It was self-defense. I don't know why I'd do that? I'm trying to role-play, not min-max or 100% it.

That was irony. ;-)

And the sad thing is that I couldn't tell because I know some people would say that unironically. Like youtube comments on an RPG yelling at the one playing that he didn't choose the "optimal" option.

"You idiot, when you start playing the game you IMMEDIATELY head to Hills of Pestilence which you obviously find by giving exactly 4 coins to the beggar in the eastern corner of starting city Mellistia, and there you go for a Belt of Giant Strength which sets your strength to 20. You didn't even count on that while creating your character and put more than 2 points into strength, you're such a stupid cunt. Who doesn't know that before starting the game for the first time!? You totally ruin the game you fuck."

Then you watch too much Youtube. The comment was oozing with irony. Not that it needed it, but the smiley at the end was a dead giveaway: acerbic comments don't end with a smile.

Those people exist, no doubt about it, but I'm detecting a little cynicism.