8/皮老师，concurrent H1B questions

I'm a full-time software programmer under H1B working for company A. Company B is asking me to work on a short period contract job. Company B doesn't want to do anything to jeopardize my legal status. My questions are as follows.

1. Does company B have to apply for a concurrent H1B for me? Is it simple? What's the cost comparing to the original H1B?

2. Is there a way to save the time and money on legal fees? Here is my rough idea. If I create the project and retain the ownership of it (so I'd be working for myslef), is company B able to license it from me on a non-exclusive basis? Would this way work?

Thank you so much for any comments and suggestions.