Hi,
the integration works, definitely it is possible to connect more then one ERP system to one EWM system. You just need to be aware that you need to figure out your potential master data issues. With "harmonize" I meant some special entries and settings which are available, which have a table in EPR as well as in EWM. You have to maintain them the same in both systems - but also the same in both ERP system. But these are tables you might not even use.
"Also, do we have to harmonize the ECC systems to make sure that they can work with one EWM system?"
Not sure what you mean with that.
Brgds
Juergen