Hello and welcome.
I (and others) will recommend you read all the information on the main Saafe site as well as using the search box at the top right of the page to look for various topics - everything you have mentioned it covered in a myriad of threads.
As a starter, no, do not answer the door naked, even if a client suggests it. As a starter, think about your boundaries - what do you want to do, how you want to conduct yourself, what outfits and lingerie you are happy to wear etc. etc. Once you have figured this out, you know you limitations so if a client asks for something you are not happy doing, you can say no. And this is something worth remembering - you can say no to anything, for what ever reason you like and you do not have to offer any explanations; NO is a complete sentence. The more you are sure of yourself, your services and how you want to do things, the easier it will be for you to not let clients walk all over you and push your boundaries. As an aside, do not state you are new in your advertising as this is catnip to time wasters and boundary-pushers.
Lastly, for now at least, always knickers go on top of suspender belts so they are easily removed and you can keep your stockings and suspenders in place.