There were team cars to the #98 that were the same color and used #15 & #16. Theses were driven by Parnelli Jones and Peter Revson among others.
Before I had any idea Scalextric would be making a Cougar I bought some bodies from RMS resins and decals from SlotCars4U to make replicas, but ended up settling for the 4 liveries shown above for my Trans Am series. After the Cougar team nearly won the championship in '67, falling a point behind Mustang in the last race, Ford squashed the Mercury team to reduce competition for the Mustang.
There are pictures of this #48 Cougar online, but I was never able to verify it as actually being in a Trans Am race.
There also would have been privateer Cougars in the Trans Am series, but none that stood out. All of the SCCA race reports are available online that list every car and driver that started every Trans Am race between '66 & '72 so the history is well preserved.