My perm has started by I-140 hasnt. Would I need to restart?
their*
Keep in mind that if you are changing employer without good reason e.g. termination, you will not be able to apply for citizenship in the future. You need to wait at least 6 months after you have received your gc before it is safe to change employer. But this only applies if you are interested to become a citizen
Yes
If I-140 is received then it can be transferred correct?
Yes, then you can retain your priority date.