The best way to really laminate cordura and kydex together is with a good industrial adhesive (like a two-part cement), along with heat and pressure. Obviously you're gonna have to watch the heat with the kydex. Something like putting your gun or mold into the holster and using closed-cell foam/plywood to apply pressure.
If you don't do this, most typical glue joints between dissimilar materials will fail.
When I worked at Bianchi/Gregory they had this huge press, that laminated closed-cell foam to "ballistic nylon" for the holsters and pouches. They used "wet suit cement" along with pressure, and a little heat. The pressure made all the difference. The heat just speeded up the process I think.
I would think uncoated cordura would be best, as somebody mentioned, or find a way to break down the urethane coating for adhesion.