I am working in Company A, but company B has filed LC for future employment. Now after LC can 140 be also filed for Future employment?
---- YES, you can file I-140, I-485 concurrently and also file for EAD and AP
or do i need to join company B before filing 140
---- no need to join B before filing I-140, let them file I-140,I-485( you have to do medicals, photographs , birth certificate, passport pages and other requirements for I-485. it is up to you can join now or after getting EAD or before I-485 approval. If you want to join now the B Company you may have to do H1 transfer, as you don’t have EAD at this time
----- GC is for the future job it is always better to go with B before I-485 approval( I-485 has backlog of about 2 years and not moving in many service centers it may take 15 to 18 months minimum.
---- if you don’t have any concerns of loosing job in future then request company B to file your I-140 with CP option and you may get GC through consulate earlier, if any risk then file for AOS( I-140 and I-485) because if any problems lawyer in US can handle the AOS but for CP they cant do anything if rejected