Have you tried stewed dried apricots? (the sulphite free ones from the health food store) They are high in iron and help really well with the constipation (very similar to prunes). My dd always got constipated from rice cereal, but did fine with the oatmeal. Strained peas helped too.
Regarding the mineral oil, my naturopath recommended we use "Udo's Oil Blend" (again from the health food store). It does help with keeping things moving, but our reason for using it was to help with her eczema and dry skin. It is a mixture of flax oil, sunflower oil and a few other oils. I just mix a half teaspoon into her cereal/fruit/veg at breakfast and again at dinner.
i'm pretty sure it would be unsafe to use any iron supplements for such a young baby (unless obviously your ped says to) and iron is very constipating anyway. Also, don't worry so much about if your lo is getting enough iron... we had to cut out cereals altogether for about 2 months because of a sensitivity, and I was really worried about that (i read too much!!) but the doctor was not at all concerned. As long as it isn't really long term and she is eating a few other things and getting enough bf, she'll be fine until you can sort her out. Hang in there!!!
