Thanks for the update and the giveaway, that said we all (winners) activated the key before knowing it was the beta version of the game, personally if i would have known it was beta i would have never accepted it and asked a re-roll for a new winner, but not being aware of that it's too late now of course, since once a key is added to a steam account can't be given back even if i'd really want it to be.

Over a year ago i got suspended (by automated library checking, apparently) because a game was not activated and i guess it was a beta game not reckognized as full game, i can't really remember details other than it was very bad to get suspended and i don't want it will happend again.

Therefore i agree with you that it would be best that you contact support and take this giveaway down, since you didn't spend money buying games etc. If you contact support all will be ok i think just specify you gave beta keys without being aware of it and none which includes yourself will have any kind of bad consequences due to this giveaway, otherwise i'm sorry but i'm not going to mark this game as received because it's not the full game according to steam (which is what matters) but just beta which is against the rules to give away, thus i haven't technically received the full game that was supposed to be given away in the first place, so again not received the full game.

That said i don't blame you or anything, it just happened and i'll do my best to not get suspended this time.
I hope support can delete this giveaway (i have seen tons of time beta key giveaways that got canceled) so you will not have any not received because of all this. Take care :)

TL;DR
Quote from SG's guidelines:
"Beta keys, guest passes, coupons, and free games should not be given away."
Source: https://www.steamgifts.com/about/guidelines