You say "LR CC (Latest version) could you check that it is in fact LR CC 2015.7
Also have you tried deselecting the Graphics Processor?
I have the same issue as follows:-
15" Macbook is solely used for editing images within Adobe Lightroom & Photoshop. within minutes of starting up software, CPU % activity reaches 800%, Fan speeds increase to full speed (very noisy) and the CPU temps reach 90 deg C and upwards , determined using 'HW monitor ' . Worryingly HW Monitor reports that the 'GPU 2 Die' temp is 129 deg C.
Have upgraded OS from El Capitan to Sierra as well as fully uninstalling then re installing Adobe software. Have spoken to Adobe, there opinion is that there is a hardware fault. Also just to note before purchasing this Mac Book Pro 10th November, I was using a lower spec Mac Book Air, with no issues
Exactly the same machine spec as well. Was DdeGannes answer correct?
Have there been any solution to the problem? Or what did you do? I have the exact same model and struggle with the same problems and neither apple nor adobe is a help with solving the issue.