From what I've read, Ashley is still not minded to make the money available for Newcastle to buy him, even at that bargainous release clause. They had hoped to use Gayle as a makeweight, but as Deutsch says - if we offer £16.5m then we've triggered the clause and Albion will have no say in the matter. It will all depend then on (i) whether Newcastle match the release clause and, (ii) if so, what the player wants to do.
I'd take him in a heartbeat - every time I've seen him this season, he's impressed me and he seems to have got better as the season has gone on. We have no real competition for the front two in our squad and if we're going to stick with 3-5-2 then we need at least one, probably two (depending on Ennis' development) additional players capable of playing in a front two.