Hi,
from you description i read that you use EREs method to provision and outbound sync object to ADLDS.
Maybe you only forget to write it in your question but you will need a set also to bring the objects you want to sync or provision in the scope of the sync rule.
A MPR triggers on a set transition normally to start a workflow which adds objects to the syncrule (ERE creation). And syncrule need at leas one "inital flow" which is DN in this case.
Dont forget to import the sync rules from Portal to MV and also the ERE, since these are evaluated in the sync engine not in the portal.
Keep also in mind for outbound synchronisation that on already connected objects the "relationship criteria" is evaluated each time on export flow.
Regards
Peter