The Fi-Con scenario you are thinking of is SH14.0, Fi-Con Fiasco in module K. Historically, the Kzinti 23rd Fi-Con Flotilla was mauled in battle in Y181 by Kollos Kumerian's 701st Gunboat Flotilla (a Klingon G1 group). The Kzinti were not the only race to employ Fi-Cons, my hydrans did as well with the Valkyrie PF.
As for the Gorn, they as said couldn't fit into standard fighter cockpits, so they hired Skolean mercanaries to fly their fighters. This is one reason the gorn lagged all other races but the lyrans in carrier development. Gorns used fighters bought from the federation, including the G-10, G-18, G-20, G-8, and G-12 fighters. These were the same as the federation types with plasma D or F rounds replacing the missles. The only home grown fighter shuttle types used by the gorn was the G-30 Wyvern and the bomber types, which were large enough to accept Gorn pilots (the G-30 being a heavy 2 space fighter).