You should apply for I140 with the other personal's LC. When I-140 goes through, you are ok. Don't do I140 and I 485 at the same time, it will make thing more complicated. Sorry that I did not notice your question earlier. By the way, when you own LC comes, you can apply I140 also. But don't do I485 at the same time, so that one of them go through, you came I485 with confidence. Good Luck and the USCIS.