Hi DLS!!!!
With regard to your question about the oats or potatoes in the meat mix, when you mix eggs and oats with ground meat, it acts as a binder and holds the patties together. My mum does this when she makes meatballs and meatloaf. It helps the meat to retain its shape once formed, rather than falling apart. It does not affect the flavor of the meat in any way.
Cheers,
Micah