CDG and AMS aren't a problem because those lounges are operated by AF and KLM respectively. The issue is *contract* third-party lounges when a SkyTeam ElitePlus (including DL GM+) departs on a DL operated flight but is not confirmed in D1. If the lounge is operated by a SkyTeam airline (or SkyTeam itself if there are still any such lounges---LHR had one when some DL flights were not in the same terminal as VS), and SkyTeam ElitePlus departing on a same day SkyTeam international itinerary is eligible to enter.

As mentioned above, VS lounges and VS flights have their own rules.