If cps is following a friends pregnancy due to a dirty ua for pot, will babies meconium be tested at birth? Or just blood / urine?

Depends. In my state, if your friend is on the CPS watch list, every hospital in the region will be on notice and both urine and meconium would routinely be tested.Since meconium can retain any banned substance for months after use, the only way to stay out of trouble would be to abstain.You didn't identify the state, so I don't know if this applies.
You tell us. This is an international web application. We have no connection to the specific CPS or even know where you are. This question is not going to be answered here. We do not know.