Nope! You can sew all of Marsha's closures with a regular presser foot. You might find a zipper foot handy for those instances where you need to get really close to an edge, but it's not absolutely necessary.
Whenever you're ready! The lessons are available online any time, and your access to the class never expires.
As long as you need! Your access never expires, so you can come back again and again.
Ask your questions on the platform and you'll receive instructor feedback. Your fellow students are also likely to jump in and offer advice from their experiences.