alright, so, Katherine at one point did frequent jobs, but as she has made more and more money doing more and more dangerous jobs, she has begun to do them less and less frequently. Though now she rarely shows up at the hideout to do jobs (Just the bare minimum), she is skilled at sneaking and fighting and always takes the most dangerous jobs they will give her (Dangerous jobs that she is known within the thieves guild for doing). Though she has not told much about herself to anyone in the thieves guild, her name should be recognised or at least slightly familiar to anyone who has been in the thieves guild for a while. She certainly does not consider anyone in the thieves guild her friend and does not give any impression she does.

Wow, i should have put all this in the submission. Whatever, that should give an idea of how she interacts with the thieves guild

As for where they will be at the start of the roleplay, I suppose Katherine will be in Helgen sifting through the wreckage of her house that got destroyed in the dragon attack, Zakariah and Uriel will both be in Whiterun (No reason they are both in whiterun, they have no connection).