It's silly that Lionsgate is trying to keep the second trailer exclusive. Might as well release it everywhere, so everyone can see it to build up hype. Trailers are suppose to be EASY for viewers to find, not a hassle!
I think you have it backwards. Yahoo probably sought after and paid Lionsgate for the exclusive rights. (They're kinda desperate to stay in existence.)
Either way, it's a dumb move for all the reasons you mentioned.