How do I? Texturing

Very new and trying to figure out a workflow. Very simply texturing small architecture to use in Unreal. I love what Substance can do as far as detailing. But I also wanted to make use of vertex painting within Unreal. For things like walls with multiple textures (weathered and broken plaster over brick?) (moss on wood?). I feel I have more options for detail if I create the main texture in Substance rather than vertex painting both textures. But can I bring in the mesh w/ the base texture then paibt over it? Or maybe just do that in Substance itself.
Thanks for your help