Can active duty who get in free bring family from out of town who dont have an ID an get them in free?

Nope. But theres free musems every Tuesday!

https://www.sdnhm.org/visit/ https://www.sdnhm.org/visit/residents-free-days/ https://www.sdnhm.org/ Check the official Website to be certain & current.

No

1 per ID

Nop.

The free museums are only for residents right?

No. Dependents with ID are not free either.

No only if you have a military ID.