Avatar or Expansion of Krishna: Kalki

                                                                  Q. 1. I'm confused on the subject of yuga avatars in this cycle of Kali. Gaudiya Vaisnavas claim Sri Caitanya Mahaprabhu as the avatar for this particular cycle of Kali yuga. Since he has already appeared, will this kali yuga end without the appearance of the Kalki avatar? This seems to contradict the Vishnu Purana.

                                                                  Q. We know that Krishna will incarnate as Kalki at the end of Kaliyuga but in the text below it doesn't mention anything about it. Isn't Kalki avatar considered as Krishna or Supreme himself? In the purport Srila Prabhupada explains about Chaitanya Mahaprabhu in Kaliyuga but there is no explanation on Kalki avatar, even as assertion of Krishna? Can you please explain the Kalki avatar mystery in Kaliyuga?

                                                                  *In SB 7.9.38*
                                                                  ittham nr-tiryag-rsi-deva-jhasavatarair
                                                                   lokan vibhavayasi hamsi jagat pratipan
                                                                  dharmam maha-purusa pasi yuganuvrttam
                                                                   channah kalau yad abhavas tri-yugo ’tha sa tvam