Honestly, I think maybe the ''guests'' Brad was referring to could have been Steve Aoki or Beck and whoever else they used to have do their live strings and stuff in past albums. We pretty much know that LP and Steve Aoki will be doing a song for TF4 and it will appear on 'Neon Future', which is Steve's upcoming album. It could even be a case of what Owen Pallet did with IBG back on LT. I don't think there will be any more vocal guests, I guess, is what I'm saying. Mike is the primary writer for the band and he knows a lot more than most of the members, so I am going with him on this. Chester was also asked a similar question in a recent interview and he only talked about Rakim, saying it was rare for them to have a guest and no one else could have done it, etc.
As for the new song coming out before the album, it could very be the song they are doing with Steve Aoki for TF4 and I'd be fine with that. GATS is enough to hold me over until June, honestly, but if they release another song from the album before it comes out, that'd be awesome too.
Honestly, I am super happy that Rakim might be the only guest on the album. I don't want tons of guests on a main LP album, save that stuff for live performances or remixes, etc. Rakim is fine.