Is it OK to mix or combine different types of attic intake vents?

Yes, because intake vents are installed in the same pressure zone they would all work together to be intake vents.

Yes, because intake vents are installed in the same pressure zone they would all work together to be intake vents. For example, you could install The Edge Vent (installed on the roof at the roof's edge) in conjunction with rectangular undereave vents (installed in the overhang of the house).