Resource ECF update via transform

Not sure if this is possible, or recommended (which is why I am posting). 

I want to be able to update our PWA resource fields (and associated ECFs) with a SQL transform from another SQL database from our HRI system.

I have found a PWA MSP_EpmResource_UserView that seems to have exactly the fields I am looking for. So it seems to me it would be very possible that I can update the resource fields/ECFs from data from another datasource.

So my questions are:
1) is there any reason that I should not be doing this?
2) Is there a better/recommended way to do this?
3) is it possible to do this with an Active Directory user/group sync (assuming that  this information is in AD custom fields).

Any thoguhts, comments, suggestions or otherwise would be more than welcome!

Thank you!