Solo 401k

[Gardi A.]

hello all 

my name is gardi and i'm new to Biggerpockets and had a question about Solo401k.

1) can you fund it on a monthly basis. so once i set it up can it be funded monthly similar to a regular 401k or no?

2) is it rue that you can rollover any other IRA into a solo aside from a Roth IRA

3) does a Solo 401k come with a sub roth build in

thank you