As Yawgmoth said, it wouldn't matter. The exact text is:
Originally Posted by Rites of Spring
Your character can belong to only a single seeming, but she also possesses the kith blessings of both kiths. No other benefit of the other seeming is transferred; your character is still a member of only one seeming, with all that entails.
So, in list form, the character with the dual kith merit and kiths from two different seemings has:
- Seeming blessing from initial seeming
- Kith blessing from seeming-related kith
- kith blessing from non-seeming-related kith
- Affinity with universal contracts
- Affinity with seeming contracts
- Curse from initial seeming
The character does not have affinity with any contracts that are not universal or on their seeming's list, even if the contracts are affinity for the seeming providing the character's second kith.
An Antiquarian Author Darkling, for instance, doesn't gain affinity with any wizened contracts, like artifice. He would only have affinity for the standard Darkling contracts.