In the sense that they are friends, are competing for the title of PK and has similar OP devil fruit as WB, he could be considered as such. But strength wise, Blackbeard will be the closest to being the WB to Luffy.
Yes, I don't say OP doesn't have parallels, but what I've been implying is that people are taking them too far. In fact, the only parallel which Oda should do is Roger & Luffy - and in that sense, their similarities only intertwine due to their beliefs & willpower.
Furthermore, Oda has done the best he can to not give OP the same cliche-ness that almost all other Shonen's have. Hence making all these parallels that so many people are spewing on about ruins his track record and ultimately ruins OP's unpredictability factor.
After Blackbeard is defeated Luffy will go on to be King of the Pirates and there is no need for yonko if there is a KotP... I think the war will be after that too