I know a lot of us are like: LC(Perm), 140 approved, 485 waiting

There are 3 sayings about the situation of being laid off when waiting for 485 PD, which is correct?

1. If I change my job in similar category, I CAN keep my priority date so long as my OLD employer doesn't revoke my LC and 140. But I have to redo a PERM LC and 140 with the NEW employer, also a new H1. then when the PD for EB2 comes, I file 485 using the NEW employer (but the PD is based on the LC with the OLD employer)

2. If I change my job in similar category, I CAN keep my priority date so long as my OLD employer doesn't revoke my LC and 140. And I DON'T have to redo a PERM LC and 140 with the NEW employer, I only have to do a new H1 with the NEW employer and I CAN use the old LC and old 140 . then when the PD for EB2 comes, I file 485 using the NEW employer (but the PD is based on the LC with the OLD employer)

3. If I use PERM, then so long as I leave the OLD company, everything has to be redone: H1(of course for sure), PERM LC and 140, and the PD will be based on the NEW LC. In short, the only situation that I can change job without affecting PD is 180 days after 485 filing.

I think a lot of people are like me. Please clarify if you could. Thank you very much!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!