JDS couldn't stop the takedowns of Velasquez in their second and third fight. What makes you think at this stage in his career that he'll be able to stop Cormier taking him down. Also Cormier beat Barnett, Antonio Silva (coming off his win against Fedor), Jeff Monson, and Frank Mir just to name a few at heavyweight. Also I like how you showed the very first JDS fight which didn't even last that long not to mention Cain came into the fight injured. Not taking anything away from JDS but Cain wasn't 100% and the second and third fight proved that. He mauled JDS in those two fights.
DC beats JDS the same way Cain did
DC beats Overeem via cardio. I can see him tiring Overeem out early and finishing him later on in the fight
DC beats Werdum and I think it'll be via him taking Werdum down, getting back, rinse and repeat which will tire out Fabricio. He'll then pick him apart on the feet and finish him.
The hardest fight will be against Stipe and I would pick Stipe to beat him.