There may be some confusion about what experts are able to do for you. We cannot give advice or solutions. We can answer your questions in general terms and tell you what the procedures, policies and law are.
You would then be able to use that informtion for an informed discussion with your attorney on what they can do to solve your particular issues.
Will revoking application to made by company B and applying new and fresh by company C for new H1B help? You cannot do that because you have left and and have to pay stubs to show you remained in status with A. Withdrawing Bs petition would collapse your bridge and assure the denial of the extension of the petition for C.
If company C files using company B's visa application fee receipt and I keep working for company B, till visa approval comes, will there be an issue in company B's approval since company C is filed a premium visa before approval of B?
USCIS may approve C but if it turns out down the line that B's petition is denied then you bridge was collapsed. USCIS has re-opened the petitions for C and revoked the I-94s based on you having been out of status as the result of having left A and B and B being denied.
If my application has reached in mid April, till when can I hear back on decision for B from USCIS?There is no way of knowing for sure. USCIS may be investigating B for reasons you might have no knowledge of. They may have had an H1B employee file a complaint against them with the DOL, they may have hired a large number of H1Bs, they may use end clients and there might have been some issue with an end client. There could be a million reasons for the delayed approval and all out of your control and having nothing to do with you. I am just throwing out examples of issues that can come out with any case.
What is the best option/advice in such a case? Safe and sure option.The safest action is to wait until B is approved before moving onto C.