M.H.
HI Amy,
Cradle cap is systemic so it's coming from her diet. Is she breastfed or formula fed? Formulas have a lot of preservatives in them and chemicals that little ones can have reactions to. If she's on formula you may want to switch her to goat's milk or almond milk. Both are very nutritious.
Renew Intensive Skin Therapy lotion is the only thing I have ever seen get rid of cradle cap, eczema or psoriasis. It's not greasy like the other things you've mentioned eithdf. There is documentation on the long lasting healing effects of it and how it is so much better than even the prescriptions like eucerin.
Hope I helped!
M.