3 I would show yourself as people like to put a face to the course, it personalises it and makes you look available for them.
4 you choose the rate however I strongly advise you to check out what your competitors have set, what length their courses are. Plus opt into Udemys discount programme, understand that we sell very few full priced courses but do sell a great number of heavily discounted courses.
5 your course must be a least 30 minutes long, they have guidelines available for you. I strongly recommend to follow their excellent instripuctional tips of course preparation, this is free to you.
6 most of all have fun. If you have a look around here you will find the answer to many of your questions. Good luck bringing your course to life.