The problem was created by GSP's effort to gain weight to get bigger for the 185 division. I doubt he will fight at 185 again. It makes no sense. He fought at 170 comfortably for a decade, my guess is that he fights at 170 or 155 next or perhaps a catch weight somewhere in between with Conor if the stars align, GSP is healthy and Conor decides to fight again. Conor losing to Ferguson or Khabib is bad for his brand. Conor might want that GSP big $$$ fight before diving back into 155 and potentially losing. If he loses to GSP, he can say I lost to a bigger man who was probably the best ever at WW. No shame in Conor losing to GSP. Gassing after a round or two and getting brutalized by Ferguson or Khabib is another story.
Conor also might also prefer to wait to dive back into 155 by letting these guys beat each other up and wear down plus Khabib and Ferguson are very large for 155. As they get older, they might have troubles making the weight for title fights. Conor has plenty of $$$ in the bank to wait them out. I would not be surprised if Conor fights GSP or Nate before he jumps into the cage with Khabib or Ferguson. Khabib does hold the belt so he might go there first. He will definitely avoid Ferguson...There are also possible rematches with Poirier and Alvarez...