回复：回复：that's wrong. green card is only for a future job

The last question is...Can I still keep my EB-3 full-time position at company A at the time of submitting EB-2 I-485?

you better check this with your attorney, like I said, it depands on the confidence level and experience of your attorney. if your attorney did similar cases before, then you may not have a problem. otherwise you may have to start to work for the company who sponsered your EB2

For PD carry over, you need to have EB3 140 approved then you can use EB3's PD on your EB2.

your plan required good timing. if you want to carry over your early PD from yoru EB3.

So talk to an attorney to see if your plan has any problem or not.