L1B to L1A - Possibility to change my category from EB2 to EB1

[vijay365]

I am on L1B and my GC process is in PREM - Advertisement process. My L1B expired and extension is in a process from L1B to L1A. If I get L1A visa then how to proceed my GC.

1) Can I wait till I get Labor Certificate and date then request my employer to move me to EB1 category

2) I am single and planning to marry an India girl who lives in India. Do I need to wait till marriage to convert from EB2 to EB1 category?

3) At what stage, i have to hold GC process for my marriage and bring my wife to USA if my GC process moved to EB1 category?

Please suggest me next step.