Questions about my old gifts

Well for Bioshock 2 you could always just make it a Bioshock 2 Remastered GA (since it is included if I read it correctly) for the others I have no idea really
You could chose Garry's Mod or CS:S as a GA and then just gift the other game with it, though you woulnd't get any cv this way for the second game

I don't know……Maybe you could send a request?

Create a support ticket under "Add Game To List" or "Other" and ask the staff.

For the first one, you could simply make a Bioshock 2 remastered giveaway. There's no collection including both, as far as I can tell, in the store at the moment. If you give it away as the original Bioshock 2 you'll get 0 CV. The DLC will be like a bonus to the winner.

Second one also lacks a storepage. Garry's Mod has been bundled, so if you want to get some contributor value for your gift, give it away as GS: Source. Then Garry's Mod will be like a bonus to the winner.

3rd one should just be given away as what it is. Sometimes different regions gets different AppIDs, but they're still the same game. Does it say anything about regions where it has to be activated, or is it just marked as RU? If you're really unsure about the gift, you can give it away to some Russian group.

The best thing here would be not to give those away. First of all, it's complicated and second, they might become rare collectors items in a few years.

This version S.T.A.L.K.E.R.: Shadow of Chernobyl available in RU Steam store. And link correctly work in Russia

Those are collectors items. If i was in your shoes i would keep them :D Would love to take them off your hands tho :P

Short version: 1 and 2 are safe for giveaways, while 3 is a definite no-go due to API issues.
You can submit tickets, but they're unlikely to be accepted due to various problems (missing store pages, wrong API recognition, missing price).

Long version:

1. seems to be a preorder copy, either subID 2780, subID 2916 or subID 2918, you can either:
   • submit an "Add Game to List" ticket for "Bioshock 2 Preorder" (no clue on the price),
   • safely give it away as Bioshock 2 Remastered, in that case the DLC will be a nice bonus for the lucky winner;
2. this is a package that was available from late 2013 to early 2015, subID 219, you can either:
   • submit an "Add Game to List" ticket for "Garry's Mod + Counter-Strike: Source" - no clue on the price, probably something around $25 - $30,
   • create a giveaway for Counter-Strike: Source (with Garry's Mod as a bonus for the winner), don't forget to mention that this package can't be activated in Germany;
3. this one is an older, separate, RU+CIS (and Russian language only) version of the game with a separate appID, that's thus identified as an entirely different game by the Steam API, so you can't give it away as the Shadow of Chernobyl registered in the giveaway database, as the winner would result as having a not activated win (they could even report you for a fake giveaway);
   • an "Add Game to List" ticket is unlikely to be accepted, to avoid people erroneously giving one as the other and getting winners (or themselves) in trouble;
   • compare the international version with the aforementioned old RU+CIS version.

Unless you decide to keep them, because as others have said above, they're considered rare collector items.
And no, these questions weren't stupid at all, if else it's Valve's/the publishers' fault for using a non-intuitive naming system.