Don't worry about idling. When your machine eventually needs a regen, it will perform it. The Kubotas start flashing an "RPM-Up" warning light if you aren't working at a high enough RPM, in addition to a light indicating a regen is occurring. Probably the Deeres have something similar. I've had two Kubotas with DPFs that perform regens and I've never worried about idling for too long. Last fall I was working out in the field trimming a waterline at night; I left my Kubota idling for an hour and a half just to provide lighting. Not a care in the world, and nothing bad happened to the machine, either. Idling a lot simply means the DPF will fill up a little faster with soot, and you'll need to regenerate more often. No big deal.
As far as safety features, does Deere "require" you to set neutral and the parking brake on an HST machine? I mean, if you DO engage neutral, the brake should definitely be on. But with an HST, it pretty much doesn't move. However, I'll make the following caveats to that statement:
-The tractor is more likely to roll the higher the HST range you are in (e.g. it will roll easier in High Range than Low range).
-On any type of slope, HST can still roll and the parking brake should be applied. Just use your head.
The seat safety switches can usually be defeated easily. However, I've never done it - you just get accustomed to getting out of the seat with the tractor stopped and your PTO off and your feet off the pedals.
Enjoy your new machine and post some pics!