pro-student

Yes this is possible just as it is possible to work as a RNFA without any advanced practice credential. The problem with your question is the (incorrect) assumption that the RNFA is an advanced practice role. Any nurse who is appropriately credentialed as a first assistant can work in that capacity in any setting that will hire them. This is true regardless of any other credentials they may have. For instance, a PMHNP, NNP, CNS, or any other alphabet soup combo could work as an RNFA because doing so is under their RN license and not their APRN license.
Now, if you're thinking about NPs who both first assist and round/care for pts outside the OR (writing post-op orders, following up, etc...), then the most appropriate certification would be acute care. But there's no reason your APRN license would restrict your ability to work in a capacity that does not require such a license.