Giveaways won, bundle games and regifting issue

Is it consider as regifting if I giveaway same game that I won already but recently got another copy from bundles? For example I won The Carnival last week, but I bought a bundle and got 2 extra copies of that game right now.

No, and it's not against the rules in any way.

Can I join giveaways of bundle games which I gave someone else from SG? Like I bought HIB Jumbo and thought that I won't play Shadowrun, so opened a giveaway and sent someone else. However, I don't have that game in my inventory and it's available to join its giveaways.

Yes, as long as the game is not in your library you may join GAs for it. Even if you have it in your inventory (as a gift you aren't planning to give away) you may, although that's a little obnoxious.

No and yes, respectively.

You can post a game you've won, as long as it was added to your library. If you win a game here and it isn't added to your Steam account then the site assumes it's a repost.
I've had this problem before too. Maybe just leave a note in the giveaway description explaining that you did accept the won giveaway but then happened upon a new key and wanted to give it away. No harm there.

NOT OFFICIAL:
It seems to me that regifting would apply to a gift you win here and try to give
away again, thereby "regifting" the game. Games you obtained from other
sources are just that... games obtained from other sources. If you already
own the game, giving away your extra keys doesn't seem like it would be a
problem. (?)

DISCLAIMER:
I am not an admin here and what I have typed here is my personal "common sense" interpretation. I came to this discussion hoping to learn more specifics about those issues myself. For example, here's a question:

QUESTION:
What if I were to enter and then win a giveaway for a game I have in my collection but I added it a while back and forgot it was present in my Steam Library? I know that in at least some cases (hopefully all?) this website will prevent me from entering the giveaway in the first place because it exists in my Steam account.

On the other hand, maybe the site doesn't know that I own that game... Maybe I have just today entered the key I already owned and downloaded the game and haven't synced with Steam since before it was in my library. In that case, steamgifts.com would be unaware that I already own the game. If I then win a giveaway for that game, I would have a key I couldn't do anything with because that game would already be present in my Steam Library.

If I were to re-gift it, well, that's against the rules, right? (I know it happens, but there are penalties if the giver creates a support ticket notifying Support of the bad behavior.) Should I, the winner of the "extra key" in this hypothetical giveaway, open a support ticket, or should I contact the giver directly so he or she can submit his or her own support ticket to have the key reassigned? Should I just tell the giver the key (hopefully he/she will have a record of it already) so the giver can create a new giveaway?

That last (third) option seems messier than the others because Support would have to be notified anyway so my account's win could be removed and and the key/etc. could be made still available for use—or given to another randomly-selected entrant—by the giver's account.

Thanks for the clarification, any and all who can respond to this discussion with the site's actual rules regarding the queries posed herein!

you can create giveaways for a game despite you wining it. the only rule is you must have all won games in your account.

you can enter any giveaway as long as you don't own that game/dlc. if you enter a giveaway for a package, you might get rerolled based on how many items you own from that pack (the ga creator has the final word on this).