Using A C++ Gamemode to then use Blueprint HUD

I’m curious if it is possible to use a blueprint for controlling the HUD, but using C++ to invoke a blueprint HUD and use that.
For example the HUD Class in world settings would be part of my module. In C++ I would call a blueprint, which would be my actual HUD.

Yes, you can definitely do that. If you make a blueprint of AHUD, you can point the world settings directly at it. If you make a native subclass of AHUD, you can add whatever you want to to that, and then make a blueprint of your own native class to extend it.