If it's a KLM or SkyTeam partner lounge (and not a contract lounge, in which case a lounge invitation is at the discretion of KLM but you would certainly expect to get lounge access), then yes on the basis of a WBC international ticket and yes on the basis of a PM SkyTeam ElitePlus flying a same day SkyTeam international itinerary.

Your SC membership probably wouldn't matter here unless this lounge is on the list of nonSCs that honor SC memberships.

BTW, the lounge locator on delta.dumb is pretty good if you use the drop down menu to specify access method and read all of the footnotes and definitions carefully.