Can I just say that every time I see your name, I keep imagining you're saying everything in Batman's voice?
I can already picture Adonis' eye twitch as the beast purposely keeps him from getting alone time with a Bearer he's interested in. All the while, the creature itself happily snuggles close the Bearer like an over-sized puppy and then gives Donny a look smirk as though it's saying 'I get to have them all to myself ' making Donny smile dangerously as he talks to the beast in a low tone once the Bearer is out of earshot 'now look here, you little- '
Damon would likely do the exact same thing; I already have this headcanon that aside from taking in normal animal strays, he has actually gathered some rather...unique pets during time on the run. In fact, the most normal mythical beast he ever befriended is a Chimera and that says something.
I always imagined that if Mia (female Poseidon Bearer) ever befriended a mythical beast, it would be a Sea Dragon of some kind (maybe like a member of Leviathan's family). You see, in many legends, female Dragons are quite rare to find, to the point that a great deal of male dragons never really come to have a family of their own. So Male Dragons can become quite attached to females of other species (particularly humans), which is part of the cause a number often seek them out. So imagining a big, deadly Dragon being doting and adoring toward Mia, all the while snapping at the human/non-human/demi-god males (not matter if they are an RO or not) it quite hilarious. That, and it would add a hint to the blood bond Mia has to Saint, who the Dragon never snaps at not matter how close he gets to Mia (due to sensing the fact they are related).
Oh, Harris definitely seems a little awed by the Bearer, but it seems more linked to the Bearer being a upperclassman like Cally to me personally. It might just be a matter of perspective at the moment; maybe the update will show more interactions to see if Harris' sense of awe comes from the Bearer being a upperclassman or the Bearer being the Bearer.