Training website startup

I am currently working with an IT company and am planning on a startup. I do not want to quit my current job. My idea is not very much related to my work either. My startup idea is about a training website were users can learn about basic scripting/programming technologies such as Microsoft Powershell, basic unix Shell Scripting, Microsoft Excel etc.. I will be accepting a fee for each of these courses. I need advise on the below:

1. I do not want to register as a business/incorporation yet. I will be accepting payments via payment processing companies like paypal or Stripe. Is this legal?
2. I am on an L1 VISA, which does not allow me to work for any other organization. But my wife has an L2 visa and EAD (Employment Authorization) and is allowed to work in open market. Can I accept payment in my wife's bank account?
3. My training content is on Microsoft products such as Excel and Powershell. Is it legal to provide paid trainings on these products without the consent from Microsoft?