Questions about TFT I would love to know

If you get on a unit and then build a red buff, does apply red buff to all the targets hit? If you get and a , does it deal the % damage to all 3 targets? Does it splash also on the other 2 targets? Do red buffs stack if you have more than one on a unit? Does stack? Does and stack if you have more than 1?

So many questions that I'd love to know.