Yes CN's are currently worth 56% of the Market Capitalisation...

Yes CN's are currently worth 56% of the Market Capitalisation (MC) of CLZ and the lower the MC the greater that percentage will be as well as voting rights.

IMO:
For total transparency CLZ should provide the details of the CN holders but I would doubt that CLZ would ever do that!

Probably the only way shareholders may find out is if CN holders held a majority of shares after conversion and appeared in the list of top shareholders.

When CN's are not converted they may remain anonymous until they are required to be identified (eg. a major creditor at liquidation) or when listed as a liability in the balance sheet as they maintain face value when not redeemed and that value is maintained when the redemption period expires so it becomes a long term liability until 1st June 2025.

Why weren't CN's offered to shareholders and who were they offered to? Who are they now held by?

I think these are reasonable questions given they they currently hold more than 50% of the equity of CLZ!