If these things really run at 7 m/s (I'm skeptical) the longest single stretch would be 7 minutes from Epcot to the hub. DHS line would take just 3 minutes and the lake 2.5 minutes. 1,378 feet a minute is FAST!
As accurate as you've been on timing and info, personally think I'll overestimate time to 30 minutes that way anything less feels quick.I think it will be less then that. Should be 5 to 10 minutes actually in the car per leg, and then whatever the transfer time is at CBR. Unless the lines are long you should be able to do the Epcot to DHS trip in less then 20 minutes.