Seth - he would gladly do promotional work for the shop, that sounds like a good way for them to make it onto friendly terms. Plus it would be mutually beneficial to both of their businesses too, which is nice. If he isn't allowed in their establishments I'm sure he wouldn't even know about them. He is, currently at least, clueless about anything supernatural. For Silas - perhaps when he decides to get serious about that in a concrete way, Seth could be the one to build up his portfolio for him, which would require a lot of time together which would build up a friendship, at least in the professional sense?
Hux - Absulkytely would have met them and would enjoy them, im sure. And anyone that frequents the gym is good in his opinion - including runners because he has a track that circles the entirety of the place on the second level. It's an open floor plan - so those on the track can look down and see those using the gym machines and pools.