First, there is no need to panic or worry about RFE. USCIS just need extra evidences either from the candidate or your petitioner(employer who filed H1 transfer - LLC). Being said, your petitioner will take care of replying to RFE and based on that USCIS would provide their decision.
- If RFE gets denied can I still work with abc INC or i need to travel back to home country ?
>> Yes, you can work with abc INC only if they have not revoked your visa as of now and if they appoints you back.
- Can I transfer my Visa to new company , will there be any issue if RFE is denied in current company?
>> Yes you can transfer to another company only if your visa is still valid i.e your abc INC have not revoked your visa.
What will be best step I can take before or after RFE gets denied?
>> First check your current visa status with your abc INC employer whether it is revoked or still valid. If it is still valid then better start interviewing with other companies and start visa transfer. If it is revoked then there is no option rather than waiting for current transfer's result from USCIS.