I can do most of it but, I am
struggling with generating material
instaces for each hexagon and then
communicating their properties between
both BP
Do it in the Construction Script of the HexMeshBP and assign the material to a variable.
then communicating their properties
between both BP
How to communicate will depend on how you want to interact with the hexes and what needs communicating. Can you provide an example?
If you want the dynamically spawned Hexes talked back at the HexTilingBP, Event Dispatchers would work really well.