Hello Swathi
If you want to post the backflush later as a background job, the goods movement will only be posted by the background job and the inventory won't be changed until that.
From an MRP perspective, I don't see any problem, since there will be a reservation as a requirement. Also, you may schedule the backflush job before the MRP job, to ensure that there won't be any problem.
Also, the OPKC setting is only relevant for discrete manufacturing. A different functionality is used to post the backflush separately for repetitive manufacturing. See the link below for more details:
Separating the Backflushing Processes - Backflushing (PP-REM) - SAP Library
BR
Caetano