A-4M and F-4S for 1980s scenarios. The A-4M would bridge the gap between the older Cold War tech and the later stuff that found its way into the Harrier II. In fact, the ARBS optical bomb computing system in the Harrier II traces its lineage to the A-4M. Therefore, the A-4M offers a significant option for accurate bombing in scenarios that predate the F/A-18's use of optical pods. While an A-6E might be a little onerous and difficult to correctly implement, the A-4M effectively bridges much of the missing gap.
F-4S over the F-4E, because the Echo would be a waste of plane because it can't land on carriers. Who would even want it?
But, I've been thinking a simple NATO aircraft with broad appeal would be the F-5A as it served into the 1990s and offers a simple and historical option for most parts of the world. Probably more than even the MiG-21.