So, as it happens, those export studies were next up. (PXM turns out to be a rabbit hole -- Friedman and this brief only referenced one of about a dozen configurations that were done under PXM around 1985-86, with multiple different hull technologies and equipment standards. That's probably going to be a separate thread at some point, when I get to the bottom of it.)
The FMS export frigate studies were done by Gibbs & Cox for a Royal Saudi Naval Force (RSNF) frigate requirement that was eventually fulfilled by the Al Riyadh class (a Lafayette AAW variant). Combat Fleets 1995 reports that the Saudis were looking specifically at the AEGIS version. As of September 1992 other candidates being considered were a modified Halifax-class frigate with Sea Sparrow, or FF-21. Which certainly covers the full range of capability, consistent with Saudi's usual acquisition strategy.
So, the interesting thing is that there are three versions that differ only in their radar and weapon control systems -- FFG-61 CORT, New Threat Upgrade (NTU), and the AEGIS Combat System (ACS). The actual armament was fixed across the three baselines: 32 Mk 41 VLS, 8 Harpoon, 1 Mk 45 gun, 2 CIWS, Mk 32 torpedo tubes, and 2 LAMPS III size helos. Same for the EW suite, which was SLQ-32(V)5 with Sidekick and the usual SRBOC launchers plus Nixie. ASW seems to be limited to the hull sonar (SQS-56, despite the typo across all three slides) and LAMPS III helos, with no mention of towed array or VDS.
So, displacement starts at 5183 tons for basically duplicating FFG-61 (~4100 tons) with reset service life margins, a second shaft and auxiliary diesel engines, a steel and composite superstructure with some stealth shaping, and updated armament.
Swap out the FFG-61 combat system for a version of NTU and the displacement jumps up to 5640 tons. And you add about 20 crewmembers.
Jump to ACS with ANPAR (SPY-1F) and displacement rises again, to 5723 tons. (Something weird happens with beam here; the heavier ACS version manages to be narrower than the NTU version, despite being longer and appearing to have more weight high. Not sure how that happened, but stability calcs can be weird. Or it could be another typo.)