Your interest in this might have passed years ago, but the answer seems to be that any race marked with "playable" ignores HP regen in combat, except for the player and followers. If you play a somewhat rare race, say wood elf, you can very cheaply get most of what you want by making all other races not playable. If you want to play a Nord, I suspect you have to make a carbon copy of the Nord race for you to play as, while making the default Nord not playable. This will grant the HP regen effect to all the Nord NPCs in the game and still let you play a Nord-like character. This might spoil dialog responses that depend on being a native vs. outlander. Some brave soul might also try marking their race "unplayable", after already starting a game. I have not tried this yet.
