Cazatou.
Weather at Lighthouse is a Red Herring. According to Wratten negligence had taken place by Waypoint change. The only credible witness near this point (Holbrook), puts the aircraft in acceptable VMC.
Possible later breaches of CDT are again a complete Red Herring. The crew were well inside CDT at the time of the accident. Whether they intended to breach it sometime later that day is pure speculation.