are there anything more from what these ko's do not complain?
Given the size of the koyukkuri Alices, I don't think they're physically capable of climbing more than 2-3 stairs... In human terms it would be like asking you to scale a 7 foot tall wall. Repeatedly. You could do a few, but there's no way you're gonna be able to do the 50-60 required to make the equivalent of a creature that's only a few inches tall climbing 5 flights of stairs.
To be fair, everything these Alices have complained about is a legitimate complaint. Father Marisa DID identify the cough drop as a sweet sweet when it wasn't. Father Marisa DID respond "Take it Easy" to Mister first, and the cake Mister gave them WAS better than anything Father Marisa ever got them.
I assume lots of STREEEEETCH-STREEEEEETCH is involved. Maybe grab onto the lip of the stairs with the upper teeth or the tongue and lever the body over, kind of like the Reimu climbing out of the yukkurarium in Yukkurarium Family?
Considering how weakly rooted yukkuri teeth seem to be in general and how important teeth are for survival, I can't help but see that as playing Russian roulette.
Besides, didn't that Reimu get a boost from hopping on a ko-Remilia?