Thanks & yes, I got that. But this soft fork happens at 4) or two weeks later.
The question is, whether the new coded miners (SW enabled) will orphane the non SW chain down two that BAD block made in 2) because they will all agree that this BAD but old block is the last valid SW one since it contains the correct LAST correct SW entry?
No, that block will not be invalid. The rule is not enforced for any blocks before the specific block where the activation starts, all at once for everyone upgraded (including the 95%+ hashpower that triggered it). The blockchain itself assures that the triggering is coordinated and that almost all the hashpower is running software that can enforce at that coordinated point.