This may be old news to all of you Windows Linux dual booters, but it came as a surprise to me. Mysql was hanging because my Ubuntu setup was using local time for the hardware clock because...wait for it....Windows uses local time in the hardware clock! I guess mysql does not like being shutdown before it starts....Anyway, setting both Windows and Ubuntu to use UTC for the hardware clock solved the boot problem with mysql hanging.
On to my second to last issue with running Ubunu on my Surface Pro 4...my bluetooth mouse won't reconnect on reboots or after sleeping....I am singing the 'bluez' blues......
Mark