If you mean marriage certificates on PSA paper, then you're good to go with that requirement. But if the MC you have now has the NSO (not PSA) logo, you should order new ones for upload to NVC.
As for CENOMAR/CEMAR, you don't get to choose which, actually. As you've seen, there is only the CENOMAR option on the psaserbilis website. The type of document that will be delivered will depend on whether PSA has any record of the person's marriage(s). So your wife will get a CEMAR (Advisory on Marriage), and your stepdaughter will get a CENOMAR. I got a CENOMAR because we didn't do ROM, so PSA has no record of my US marriage.
CENOMAR/CEMAR is not required at NVC stage. I didn't upload mine prior to DQ. But it is definitely required for the interview. So make sure to upload a scan of your wife's and your stepdaughter's CENOMAR/CEMAR to CEAC prior to their interview. Up to you if you want to upload them before or after DQ. It won't harm their cases either way. Note also that CENOMAR/CEMAR is only valid for 1 year from issue date. I've also seen VJ reports where the interviewing officer wanted one that was issued within 6 months, so best not to request CENOMAR/CEMAR too early.