I don't see any reason to winterize THRU the filter, so I would place it in the order that you show. However, I would add either a backflow preventer between the filter and quick-connect (if the system connects to any potable water source before the main shutoff) or anonther shutoff valve (if this is a well system dedicated to irrigation) just so you are not applying the heat from a compressor to the filter's rubber elements, and you can close off the system if you ever have to remove/clean the filter.