tributed

Yes, a facedown monster can be Tributed in order to Tribute Summon a monster. But as usual, you can only Tribute Summon if you have not already done your "Normal Summon or Set" for the turn. To perform the Tribute Summon, during your Main Phase I or II, send the monster(s) you are Tributing to...

No, it does not get flipped automatically. When face-down monsters are Tributed, they are sent to the Graveyard without being flipped face-up first. If you want to activate the Flip Effect of your monster before Tributing it, you have to manually Flip Summon the monster during your Main Phase...