Yeah, I after replaying from the start, I came to the conclusion that it's waaay more likely that bull-people in Crete are a reference to Europa & Zeus-Taurus (with it all revolving around the dang island for one). However, in the world of MinoHotel, Minos (foster-father of Asterion) is a descendant of Minos (son of Europa); that also would explain the "men of certain Cretan lineage with bull features" that Asterion hears of in Hades. I can even believe Minos (father of Ariadne) is totally unaware of his bull lineage otherwise it could be strange for him to shun Asterion so vehemently, even if he thought of him a cannibal. It wouldn't surprise me to see the concept of glamour showing up in his backstory.
Now, if you allow me, Imma RUN with your idea of the bedrock being crystal ichor. I wouldn't rule out Zeus Xenios of playing a role in the Hotel itself, but in regards to the basement I think differently. You see, there are two ichor-bearers that were killed in Crete. First one, of course is Argos Panoptes (the giant) killed by Hermes; then there was the giant Talos, killed by the Argonauts (which is debatable). Not only were these two giants (one a literal giant and the other a giant in size) killed in Crete; their blood was important, Panoptes' being the first blood spilled among gods after the Olympians took over and Talos' being specifically made with a single vein of ichor; but also while Argos met his end through Hermes, Jason, descendant of Hermes, led the Argonauts who in turn ended Talos. Whose shrine is at the bedrock? Frickin' Hermes'. It might be all connected! I think the possibility of ichor on the bedrock being (at least partially) Talos', makes sense of it's command-driven nature of it's functionality. Lastly ichor is said to be nocive to mortals, which checks with Asterion's advice to not touch it.
Also I believe you are right on the money about Storm and his potential to cause trouble in the Hotel.