how do i merge two victoria 4 character inject morphs..and i want to merge two textures also

Textures can be merged using the nodes or in a graphics program like Photoshop or PSP.  If your textures are radically different, I'd blend them in your graphics program first and then save as a new file before applying it in the material room.  Using the nodes might give you an option I'm unfamiliar with unless you tie them in to a blender node.

Merging two inj morphs can be a bit tricky if they have conflicting channels.  You might overwrite something you want to keep.  My suggestion would be to apply the first one and note the dial settings of the parts you want to keep.  Then inj the second one and tweak the dials back to what you want.  I don't know if this will work but it's a place to start.

I'm sure someone with more experience in blending stuff will pop in with better advice.  I'm still pretty new to the nodes and shaders, although I'm getting better at it.

Try this for the characters: set up an animation, and inject one character at the beginning, the other one at the end. Then move the slider to morph between them, and render the frame you like best. You'll never get 100% of both characters, but that would probably be a little extreme anyway.