Deep breaths people..
I am a DO in a linked DO internship into an MD residency in Michigan.
In Michigan, in order to get an educational license, you must be in a DO internship or have the waiver from resolution 42. Yes, that is the rule in Michigan. I don't know if it's the rule in the other 4 states with required DO internships (PA, WV, FL, OH). Because of this rule, you will potentially not be offered interviews at nontracking MD residencies. (Yes, people this happened to someone I know, with a letter stating "please apply again after the DO internship.")
If you are not in one of those 5 states, because of the paucity of peds DO residencies, my understanding is that it is fairly easy to get a resolution 42 waiver as others have said before on this post.
My osteo intership includes a month of clinic medicine, a month of hospital medicine, and a month of clinic FP. If you don't do a month of clinic FP, you would have to do a half day of clinic in FP throughout your intern year. yoW!
Do not believe you have to do an extra internship year. That is bogus.
PM me if you have any other questions.