14 mo has had many ear infections/colds. i want to give zinc & acidophilus for prevention. advisable? he is on iron for low level already.

Not really.: Acidophilus will help his digestive tract, not his ear infections nor colds. I would discuss with the doctor about iron supplementation; the body artificially keeps iron levels low in protracted infections because iron serves as a growth factor for bacteria. If you are circumventing that by supplementing iron, that may cause issues.