Would give it to the winner if he/she can tell what version it was.
@lhuits hasn't logged on to the forums since January 18th, and doesn't have a Steam account linked to their profile, so contacting them could be difficult.
The
WARMACHINE: Tactics - Mercenaries Faction Bundle used to have a Steam page, but it now just redirects to the Steam homepage. Therefore, you would only get a negligible amount of points if you raffle it off here. (Doesn't look like it has much trade value, either.)
I'm not sure what I would do in your position.
But if you fail to get in contact with lhuits, I'd be happy to take the Mercenaries Faction Bundle off your hands!

(Well, it's not very clear to me what the bundle actually provides. If all those DLCs have been removed trom the store, does that mean they've been added to the base game for free, perhaps? Or is the bundle still useful for something?)
I guess what I'd recommend, is
send lhuits a private message here on the forums offering to provide the second key, and then give them a month or two to respond before giving it to
someone else. ^^
Oh yeah, I should mention: If you still have any uncertainty about what's what, perhaps taking a look at
Barter's page for the Humble Jumbo Bundle 6 would make things clearer. That's where I got the links to both keys' /sub/ pages. Only thing unclear to me is what exactly all those delisted DLCs actually provide.