Not sure about the EPO, I have been taking a little since I don't do fish oil as a vegetarian, but not a lot as I knew it could be questionable. I don't know what its called, but the reference book that lists all the drugs and there possible side effects with BFing lists EPO as level 3 (level 1 being the safest or benign).
But I would say the flax is definitely a yes! I try to get a tablespoon a day of ground flax seeds on my cereal or on a salad. In fact, my MW recommended flax seed postpartum when I was having trouble getting um, "regular" again. So its good on many levels!