Depends what country you are in and how many people work with you... And lots of other things i guess... But in the UK, as i understand it, 'escorting' is legal. But if you work from a house with other girls also escorting in there, then you're breaking the law.
I'm sure somebody will clarify further...
It isn't against the law to work in or to visit a brothel, only to run one. It doesn't matter if there's fifty of you working from a portakabin provided your name isn't on the lease, but be prepared for some problems if it is (even if you set it up as a completely 'equal' flatshare, somebody would end up having to carry the can if there were problems.
As far as I know,
there are no situations in UK law where working as a prostitute is in and of itself illegal. There are plenty of things surrounding it which are, but the vast majority relate either to pimps or to punters (apart from soliciting, which is a public order offence and nothing to do with the Sexual Offences Act).
I agree it sounds like the bloke involved is the one the police seem to be after, so she shouldn't worry about cooperating with the police. If she's worried about neighbours she could maybe start making backup plans to move in case she has to, but I would honestly just lie low for a bit - unless these pictures were taken on her premises I can't see why the police would visit her neighbours anyway? As far as I know, they do have to have at least reasonable suspicion that an offence has taken place there.