QA is needed for my posthole digger, as is a hydraulic remote circuit (various ways of achieving that - rear remotes and front diverter. Rear remotes are slightly more awkard, but more flexible in what they can do.) 3ph posthole diggers obv. don't need it, and are noticeably cheaper. Also much more of a pain and less useful...
plow on FEL? oh, snowplow. Hmmm. I don't think that's advisable on a light tractor - 3ph is probably where you should put it. Most seem to find the bucket/rear plow combo best for snow, or a snowblower/bucket
THat said, I have been trying to figure out a way of doing it with shear pins for the fun of it
I'd perhaps post about the block heater in its own post, or search here. I think you'll find for new england temperatures they aren't necessary. There are certainly enough Northeasterners and midwesterners to get a very good idea.
A cab maybe something you want to look into if you'll be outside in the winter a lot. For me tractoring is primarily fair weather, so I don't want a cab - I want to be outside. And I don't mind dressing up for clearing snow in the occasional snowstorm. But if I were using it for work, or say a very large amount of time in the winter, I'd think seriously about it.
(Sadly, in Eastern Mass I've yet to have an occasion which really justified using the tractor for snow clearing. My Tundra will drive over a LOT)