Unused regular H1B and transferring to different employer

[vine]

I am currently working for Employer A (university) on cap-exempt H1B. An employer B filed my H1B in regular processing and it is approved in Nov 2018. 

1. What happens to my regular H1 if I do not use it? By when should I start using it? What happens if I keep it unused for long time period? Can I use it after a year from now?

2. Employer B is willing to transfer the visa. I have not yet started employment with Employer B and in this case can I transfer this visa to an Employer C? Is it mandatory to work for few months with Employer B before transferring to Employer C?

3. I want to keep both the visa's. What are my options?