Herbs common to hoodoo/voodoo are also common to several geographic regions and the people that live there, I see no issue with using them in spells of another type. I generally use the herbs I can get for my spell work, I do not limit myself to those that are native to my current location or those that are native to the land of my gods.
Personal I don't like the idea of mixing patrons from different paths. I think in many ways that once one learns the lore and the mythos of a path and has a deep understanding of the gods they will find that just because two gods from two different paths do the same 'job' they do not do it in the same way and they do other things as well. Some of their other areas may contradict each other in ritual or workings. These might be things you did not initially think of.