You might be better off asking this on the Engines Forum - as far as I know, the green ethylene glycol is OK to use for winterizing a sealed fresh water engine coolant system, same as is used all year long - you just can't discharge it into the water ($$$$ fine).
The pink (or orange) propylene glycol comes in two versions, one contains a rust inhibitor; the other doesn't. So if you're winterizing the engine coolant system, you need to be sure you're using the correct stuff with the rust inhibitor.
The non-toxic "pink pop" is generally used in the head and holding tanks, and in the potable water system (sink, shower, etc.).