If the CAS has no concerns as long as the spouse doesn't return then there are 2 answers
1. your spouse is the one they are worried about
2. the connflict between both of you is of concern.
err on the side of number two and asssume they are looking for you to mess up as well.
In your case asking for OCL involvement is probably a good idea. The OCL will speak with CAS and their records and interviews will become part of the OCL investigation. They will also talk to school, daycare, doctors, counsellors and other relavant peopl in the children's lives (esp if there are live-in relatives).
Just remember that the OCL is looking out for the kids best interest and that they will be trying to figure out what the true situation is. Best to be honest with them
Good luck