The de-ice truck still visits the stand for first wave departures before passengers have boarded to pre de-ice the aircraft if conditions allow eg frost on wings. Otherwise, if it's say snow or freezing fog it's a taxi to the south stands. It is quite efficient. This is for airlines that use IDS, not sure what swissport do.
ATC have been back tracking one aircraft for the full length whilst another departs from the intersection for a few years now. I believe they can only do it during daylight.