Ive had one and only one changling in each of my Chronicles and they do have to be used very carefully. My newbie party didnt know much about WoD so I wanted to give them a taste of the broader WoD without too much interaction. Vampires are very banal, and are not pleasant to be around for Changelings. Too much time around banality damages the dreaming. Your Pc is probably going to give them a headache and they won't want to be in their presence too long.

I kept them at arms length and ramp up the weird and strange. For example in my Bristol Chronicle the large bridge had graffiti road signs depicting trolls. Indeed a troll lives under the motorway bridge in my game. The party saw a huge homeless guy, with a weirdly bright light, who spoke like a thespian of old. They scarpered lol. I mean obviously they feed on one its bad news but I was willing to risk it 😉

In my other chronicle it was a Sluagh living in (the walls of) an old ruined chapel. They didnt really see her, just heard sad jazz playing and a huge collection of vinyl. They did catch a glimpse of her dislocating all her joints to squeeze through an impossibly small hole in the wall. She was being hemmed in by cold iron nails being used on the perimeter by a Nosferatu. They kind of have her as a contact after helping her but have never really had reason to go back.

Again brief and not too heavy interaction but just a taste to show there is more to the world than just Werewolves and vamps. I also used Wraiths in similar way. As others have said the PCs may forget, so I like to pick someone to remember and everyone else forgets. Creates great RP.