H1B approved not stamp, current employer ready to file transfer

[myh1bvisausa]

Hi Experts
The subject may be similar to other thread but each case is different hence starting new thread. Please help.

I am working for company A in India meanwhile Company B approached me and we file our H1B which was approved.
But I have not gone for stamping yet as still some documents are not with me.

However my current employer A is ready to start the transfer.

I wanted to know

1) Can my Current Company A file for transfer with approved petition of Company B?
2) Can Company B do any harm i.e. Withdrawing/Canceling my approved petition before or meanwhile my Transfer is in progress?
3) What are things I should take care of while transfer is in progress?
4) Will it help or create more issues if I get visa stamped Company B petition ?
5) I see many H1 tracker status withdrawn/expired what does it mean.?
Regards
Sid

[myh1bvisausa]

Hi all, I am sure you may have come across such topic. Appreciate your help.