No worries. The matching is AND. For more specific detail, in the FAQ:
"How does matching work?
Matching is done through the AO3 matching system. The setting used for NPT is 1 request, 1 fandom, all characters within that specific fandom. This is the minimum level of matching needed for an offer to match a request."
In your letter/optional details, however, you can let your writer know that requested individuals can be written about individually or in any combination.
no subject
"How does matching work?
Matching is done through the AO3 matching system. The setting used for NPT is 1 request, 1 fandom, all characters within that specific fandom. This is the minimum level of matching needed for an offer to match a request."
In your letter/optional details, however, you can let your writer know that requested individuals can be written about individually or in any combination.