There is no way Bray Wyatt gets a headline match at Wrestlemania. The closest thing he's getting to a big marquee match is against the Undertaker, and I wouldn't bet anything on that happening either.
As for Hulk Hogan returning, no. Please no. Every other report has stated time and time again that not only are there NO plans for him to wrestle, but he probably couldn't pass medical tests that would clear him anyway. He definitely should be there to add to the spectacle and celebration of Wrestlemania reaching another milestone, but him getting back into the ring would just be a bad idea all around, especially if it's just to put another unnecessary feather in Cena's cap.
IMO, this would be an excellent collection of main event matches for Wrestlemania XXX:
WWE Championship: Randy Orton vs Batista vs John Cena (I'd really, really prefer Bryan to get his big WWE Title win at Mania but in the event that that doesn't happen, I guess I'm fine with Batista winning the WWE Title for what would probably be the last time. This match would be putting the three biggest breakout stars since the AE all in the same match against each other for the first time, plus they all have history with one other in some capacity - Cena and Orton have one of the longest rivalries in WWE history, Batista and Orton go back with each other to their days together in Evolution and the last time Batista was at Wrestlemania with in a WWE Title match against Cena. This match is the closet thing to a modern day Austin/Rock/HHH triple threat match that we never got back in the day, although not anywhere near as epic, of course.)
CM Punk vs Triple H & Daniel Bryan vs Shawn Michaels (These two matches would technically be separate bouts on the card but I'm putting them together here because they would obviously be connected during the build... the Indy heroes teaming against two best friends who once co-founded one of the greatest stables in wrestling history. Who would have ever thought two of the biggest politicians in the history of wrestling would end up putting over the likes of Punk and Bryan on the grandest stage of them all? There is definitely a couple of iconic Mania moments waiting to happen here.)
Undertaker vs Brock Lesnar (Speaks for itself and needs no explanation. Lesnar is the biggest potential name other than Cena to face Taker at this point.)