Can anyone explain to me what exactly Gene Cunningham and Wayne Gillard bought from Williams respectively?

As far as I can tell they each only got half the pie!?
It's a little confusing to me, one guy can do one thing and the other can do something else.

I think you will find that this is "commercial in confidence" thus confusing things even more.

I think the only way to test it would be for someone to 'infringe' the alleged copywrite and let the court decide. That way all the cards would have to be laid out on the table for all to see. This may not be a desirable outcome for some copywrite holders as it may well expose flaws in their claims.