@JJ Doe: I think both options sound very plausible. Lienne is a social creature, despite her job, so she'd surely spend time in local bars/cafes depending on how well she likes the usuals and the barflies and such. Staff too, of course. She and Pazel would likely get along well.
As for Rose, there's no telling. She's surely seen him around, at the very least.

@upscalerat: Coincidences, huzzah! I wouldn't mind Lienne having been asked to keep an eye on Emily now and then. She's probably doting enough and she's likely bumped into a lot of other hunters over time (within reason, of course!) so hey. 
Failing that, they could have met outside of their work duties and simply ended up acquaintances. She does buzz about in quite a few places, savory and otherwise.