Seating Chart- Families intermixed or seperate?

Separate without doubt. Intermingling leaves room for the potential of creating more family drama. With a small wedding like yours, there's probably going to be enough inter-mingling.

I would seat them separately

We kept ours separate. People like to sit with who they know well and with friends and family members they don't see often.

Maybe separate but mixed. Like Your family next to a table of his family. like every other table intermix.

I have a similar situation. We decided to mostly seat people together with people who they know. When I’ve gone to weddings it’s been fine to sit with new people but I always was longing to sit with my friends and enjoy the day with them. People can still mingle in other areas but for seating we’re mostly putting people with those who we know they love. Some groups are small so we’re doing like half of the table knows each other and is being introduced to the other half of the table if that makes sense. That way people are still with people they’re close to, but not entirely alone with strangers (yes we’re ‘family’ now but still strangers).