Would you use a myeloablative or reduced intensity conditioning regiment for a pediatric or AYA patient who does not recover their counts after treatment for AML, but remains disease free?  

I would use a myeloablative regimen, if medically fit and eligible. In fact, I would worry that there is a residual disease (that you're unable to detect) behind the lack of CBC recovery which is another reason to use a myeloablative regimen.