Hi Douglas,
I'm using MBP 15" 2015 with 16GB RAM no external GPU. Playing first shooter game in Windows 10 Pro.
The average package temp of the CPU is around 60 ~ 80 C when playing in room temp. 45 ~ 60 C when idle or no process intensive Apps are running.
MBP Display Setting:
Resolution: Default
The settings I use on Parallels 15 (Home Edition) are:
For CPU & Memory:
Processors: 2 (Recommended)
Memory: 8GB
Advanced Settings: Parallels
Adaptive Hypervisor: checked
For Graphics:
Memory: Auto (Recommended)
Resolution: Scaled
Advanced Settings:
Vertical synchronization: checked
Automatic graphics switching: checked
Hope this helps.
Cheers