Did you check your coolant level by any chance? Topping it off might fix the low/no heat condition. But yeah, probably a good idea to let the dealer "handle" it.
Possible your SHO had one of the weaker PTU units installed. You had no shifting issues whatsoever before they replaced the PTU? Normal to have fluid leak out of the overflow vent when it is hot. But, PTU should not get that hot if the PTU fluid is in primo condition (and you are not trying to run 600 AWHP

). It may have been venting for some time, till it got low enough to start disintegrating.
This is taken from an older incomplete service tip document, but ... 09-8-10 SERVICE TIP - POWER TAKE-OFF UNIT (PTU) - RIGHT HAND
http://www.fordflex.net/forums/viewtopic.php?f=3&t=1752FORD: 2008-2009 Taurus X, Taurus, 2009-2008 Edge, 2009 Flex
LINCOLN: 2009 MKS, 2007-2009 MKX, MERCURY: 2008-2009 Sable
This article supersedes TSB 08-12-3 to update the vehicle model years, vehicle line application Service Procedure and Part List.
FLUID COLOR AND DIAGNOSIS:
Automatic Transmission Fluid
Red automatic transmission fluid (ATF) is not used in the PTU itself. The RH intermediate shaft passes from the transaxle through the input hub of the PTU, where the intermediate shaft seal is located. A red ATF leak indicates fluid from the transaxle is leaking past this intermediate shaft seal contained in the PTU. Use the seal kit, which contains four pieces: the intermediate shaft seal, alignment washer, deflector, and seal protector tool. The intermediate shaft seal, alignment washer, and deflector need to be installed individually and before the seal protector tool is used.
Brown/Black Fluid Indicates a True PTU Seal Leak
Use the seal kit, which contains five pieces: the PTU cover seal, intermediate shaft seal, alignment washer, deflector and seal protector tool. The intermediate shaft seal, alignment washer, cover seal, and deflector need to be installed individually and before the seal protector tool is used. Use seal kit, which contains the PTU cover seal, intermediate shaft seal, alignment washer, and deflector. All four parts need to be installed individually.