About giftaway

No.

Nope, you can't.

You should only enter to win giveaways for yourself, and if you win a game, it must be activated and redeemed to the Steam account used during registration.

you can but you will get suspended, and eventually banned. ^^

activate all wins in your account and mark as received after that.

All games won must be activated on the winning account.

Please be sure that you want the game, as you can't just go and remove it from the account later either, as it would then show as unactivated.