As others have said - just make more marinade and don't take the unnecessary risk.
I am sure that 99 times out of 100 the marinades will be fine. However, I don't want to take the chance that one of my children, nieces, nephews, etc will be that 1 out of 100 that ends up having problems.
Another factor - the second time that a marinade is used - there will be less salt, sugar, flavors, etc to be absorbed by the meat for your next cook. So not only will your second product possibly have cross-contamination issues, but probably be less flavorful as well.
