I highly encourage the use of latex dental dams for oral sex; cling film is more porous. When it comes to safety, you wouldn’t need to use a condom with your wife but it would be required for the courtesan- if your courtesan can use a female condom it simplifies the matter of needing to change condoms when swapping between women, (putting one on for the courtesan, taking it off for your wife, putting a fresh one on for the courtesan again, etc) since the courtesan will be the one wearing her own internal condom. Similar to a condom, latex dental dams should not be swapped between partners as it defeats the purpose.
If using toys, the toy would need to have a condom put on it and be changed when switching between women. Some of the ladies bring their own toys, but not all of them do. (On this trip, for example, I forgot my hitachi magic wand!) If there’s a toy you’re into, it’s best to bring it. The question on filming I’m not sure about.
Hope that helps!