A couple of Solo 401K questions

[Account Closed]

I know many on here are fans of Solo K plans. I cant find too much detailed info online and even my tax guy is not too familiar with them. So let me post my questions here for the experts

1. Does having passive rental income in an LLC qualify me to start a Solo K?

2. If I have access to a 401K at work, can I still open a Solo K? Does the max employee contribution still hold ie would it be 17.5K total in all plans?

3. Does it matter if my LLC has more than one member (other than spouse)?

4. Is the max annual contribution $17.5K plus 25% of company profits?

Thanks for your replies.