Daf Yomi - Yoma 49 - Hafshata by other Korbonos?

The Gemora learns out from a passuk in Divrei Hayomim that the avodoh of holacha will be kosher if it is performed by a Yisroel. (Rav M.M. Shulzinger wonders why the Gemora doesn't bring an earlier passuk in perek 30 which indicates the same halacha?) The passuk concludes והלויים מפשיטים - and the Leviim skinned the animals. Tosfos Yeshonim states that a Yisroel (or Levi) is permitted to do the skinning. He is bothered as to why the Gemora previously on daf 26 did not bring this passuk down as a source to prove that hafshata is kosher by a זר? He answers that this passuk is only דברי קבלה and we were searching for a source מן התורה. HaRav Chaim Kanievsky is greatly troubled by this question. Throughout Shas, whenever hafshata is discussed, it is always in respect to a קרבן עולה - this is the only korban that there is a din of hafshata, however by קרבן פסח, which is what the passuk in דברי הימים is referring to, why would I think that there would be a necessity to have a kohen do it, this is not an avodah and we cannot learn from there to the halachos of an olah? On this question, Rav M. M. Shulzinger comments, that it is קשה כברזל.