Can I initiate fresh H1b transfer by joining other employer, incase current h1b transfer gets rejected?

The difficulty here is that you have already switched over your employment to your 2nd employer without having the new H-1B petition approved. That is allowed under the law, but the complication arises when the petition is not approved. Then when you attempt to have your 3rd employer petition for a new H-1B transfer, U.S.C.I.S. will usually request recent payslips from the company with the approved H-1B petition. If you were still with the original H-1B employer, you would have no problem in providing the payslips. Then there would be no consequences to the 2nd H-1B petition not being approved. But where you have already jumped to the 2nd employer, U.S.C.I.S. might also take a look and see whether the 2nd employer H-1B petition is actually approvable before granting the extension on the 3rd company H-1B petition. The upshot is that if U.S.C.I.S. decides that the 2nd petition is not approvable, that it may believe that you have not maintained legal status. It may then approve the petition but deny the extension in the States and request you to consular process the approved petition.  In answer to your other question, there is no recognized grace period for H-1Bs where there is a denial. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.  

I don't know what you mean by an H1B transfer receipt notice.  There is no such thing as transferring an H1B.  To switch to a new H1B employer, the new employer has to petition for you. You may have a short break between H1B employers, but anything over 40 days will create an issue.