No, whether what happened during the phone call was sexual assault or not is completely irrelevant outside of MSU's internal investigation that is mostly meaningless now that Tucker has been fired. You can not have an undisclosed relationship with a vendor, it's a huge conflict of interest and is Corporate 101 DO NOT DO THIS. Had Tucker disclosed the relationship prior, he would very likely still have a job and MSU would likely be defending him instead.
The only reason CDS is relevant is because he too had a relationship with someone and then hired them to do work, so you have potentially the same conflict of interest. We don't have all the details in CDS' case - maybe the relationship was while he was at a prior job to when he asked BT to come speak to his team, maybe he informed his employer about the relationship prior to hiring her, we don't know. But it's not something you want to even dabble in, so my hope is that Batt has reiterated to CDS explicitly what is/isn't allowed to make sure we don't end up dealing with a similar situation.
If anyone still isn't understanding, go watch The Office season 5 episode 3 "Business Ethics".