You don't have to surrender something that is not valid any longer once Surrender is issued. When a surrender is issued it means you are no longer a Citizen of India. You lost the voting rights and the card is invalid by default.
I was searching past 2 years to see anything about he Aadhar. The information doesn't exist. All the info you can see will be related" can a foreign citizen or OCI or NRI can get Aadhar" and the Answer is YES and there are some guidelines not updated by the team that handles it. It was 182 days to be in India prior to the application but you can get it now straight after Landing too(excluding the processing time, you must have an Indian Address proof). I still wonder why they are searching to apply Aadhar when you already have Aadhar, i mean most of us who left Country unless the kids were born here in Canada, rest of us usually have the Aadhar including the children unless someone never applied for it.
i sent numerous emails to UDAI and never got a reply, i don't think they even check the email. As far as i am searching you will find you can get Aadhar after getting OCI/PIO status, but nothing about what happens to the Aadhar if someone attains the OCI/PIO status if they already have Aadhar. Even Quora don't have answer for it.
coming to the voter card again, it becomes invalid for sure, so no point of surrendering it. I never utilized it for neither voting nor identity purpose.