Hi Venkat,
As you are saying they are bringing new company data into ECC,
Then in my view it would be just an additional company code data to BW.
for example having two company codes X ( existing/parent company) Y ( new company)
You may need to see how that new company code reporting requirements would be.
if the user group of Y is satisfying with current X reporting formats?
etc... based on that you may need to adjust your new master data to keep everything is in sync and also you may need to develop some new reporting layouts based on new user group Y requirements.
Regards,
Naveen