Hendo is going to be in Lyoto's grill all night, but he doesn't have the speed or stamina to do it well. I think Lyoto will stun him with punches late first/early second round, then clinch and trip him. Dive on a choke or armbar immediately.
Machida looked amazing against Bader, he's made some changes and the way he moved was scary. He wants to be impressive and I don't think he'll settle for outpointing Hendo.
Hendo is a GREAT fighter despite his age, he can brawl with anyone. At this point in time Machida is just an awful match up for him.
The cardio thing is being blown out of proportion. He gassed in the Shogun fight because both of them were swinging for the fences for every round of the fight. Now, unless your name is Nick Diaz, if you fight at 100mph like that, you're bound to gas, or at least slow down considerably.
Cardio most likely will not be an issue in the Machida fight, due to Machida fighting a very conservative style. Dan went into the Fejaou fight into the fourth round (a reasonably well paced fight) just fine, and KO'd him.
As for speed, whilst Machida is much lighter and quicker on his feet, Hendo's punches come hard and fast. That right hand is like a missile, homed in and locked onto target.
The best way to counter speed is with timing, and Dan has excellent timing.