I think it’s a really good idea to use aeroway=parking_position and parking_position=deicing together with ref=DP1 (e.g.). The question is if it really is a parking position in an aviation context of if parking positions in this context are used differently.
As far as I remember (from having flown to STR regularly) those are only used for deicing. While deicing is active, traffic is routed differently as those positions are normally involved in Twys N and S traffic flow.
Concerning the Leipzig example: this is the nicest and most advanced deicing variant, resulting in short waiting times before departure → helping with hold over times. This is used on bigger modern airports (e.g. MUC as well) and definitely not used for parking .
I guess then my suggestion to have a merged tagging like aeroway=parking=position and parking_position=deicing is probably not ideal and we should have a separate tag like aeroway=deicing.
At Munich Airport (OpenAirportMap: EDDM) the deicing areas are tagged as aeroway=apron which is surely not ideal. Furthermore in Munich the facility is called deicing area opposed to deicing pad in Stuttgart.
I’d probably stick to aeroway=* tagging instead of landuse as this is very aviation specific. The yellow highlighting on the above map is not representing anything on the ground. The actual deicing positions are marked on the ground though and there is also guidance via signs to these points.
About the equipment: that is mobile equipment (deicing vehicles) most of the time, static deicing equipment exists, but that’s rather seldom.