genitalia, they would probably run afoul of prostitution statutes.

Not 100% certain regarding contact with the anus, however.

...and it seems to be a standard law for what's considered prostitution.

Basically, anything that exposes genitals or allows for genital/anal contact of any sort in exchange for money is is considered prostitution. So the list of the above activities would also be considered prostitution in Illinois, but activities like corporal punishment, bondage, and things that don't involve any sort of genital exposure or touching would be considered legal activities

One thing that makes contact illegal Philly is "penetration" which is not defined. This was used about a dozen years ago in a continuing attempt to put a friend of mine out of business. (She had actually sued the police and really went on the attack and they were out to get her.  She ran a great service with both domme and sub ladies in a well equipped and well run apartment.  Eventually she married a client and now lives happily in Florida so the story ends happily for her.) She was being particularly careful and a policeman posing as a client asked among other things that the lady playing with him put her fingers in his ears and his nose and once she did, the cops came crashing in because of this "penetration".

What is legal fetishes?

We are all here seeking adult fun.