Yes, I see your consern for glitching. Some folks have reported gitch free opperation with mounting arangements with their ESC wires close to the receiver or battery wires, but why take a risk if it's not necessary?
My ESC is on the frame plate up front, batt. above that and I have no heat issues, even with the heat sink facing the two.
All vents are cut out of the plastic canopy and the EagleTree records 92 peak -on a 32 degree day. So the only time I'ld come close to the 140 mark is on a 100 degree day. I'm running the Align 35X with 6V for an internal BEC, so I'ld think where your running a sepperate BEC that your temp.s would stand to be even lower.
As far as a ferrite ring goes you would want close to the receiver, thinking of it as a choke for RF noise emitted from the motor, ESC ,and batt. wires.
Also try to isollate the BEC receiver wire from running along side any of the RF noise contributers.