Is it okay for me to take iron supplements and prescription multi vitamins at the same time? and also is it okay to take biotin and acidophilus ?

Yes: Many (not all) multivitamins contain a small amount of iron but if you have low iron you many well benefit from an iron supplement. Iron bis-glycinate is the best-absorbed form. Absolutely no problem taking biotin and acidophilus as well.

All should be: Fine, if you have documented iron deficiency. Check to make sure the multi doesn't have iron too.