We get some info from rec guides and Golden Era TRO. Lupus, Shadow cat, Huntsman, Supernova, Firestorm.
Sources from the early Dark Age are already outdated. I think Spirit cats don't use agromechs in 3140-3150))
Sure, they can make those but you do not know the frequency- as in the Foxes take 80% of production for export which leaves the Protectorate with 4 of the 20 produced every year. We also know they were producing . . . Tempest C? and IIRC the Guillotine IIC 2? As far as armed IndiMechs . . . they may, and they may still be using things like the Inquisitor Mk II or other 'securitymechs' that they had on hand for the lowest tier defending units. Or they were relegated to training sibkos, which is very likely, and thus part of the 'last ditch' defense of Marik.
But we come back around to the point that (for some reason) the Protectorate's leader and senior Spirit Cat, Rikkard Nova Cat, pilots a Firestarter (after using a Shadow Hawk IIC . . . ) rather than something better. Or did until the Regulans wrecked him.
One thing you must remember when forming a Spirit Cat force is their evolution . . . they were a Republic splinter faction which means they drew their initial equipment from what the militia/standing guard had available, what they salvaged from fight OTHER splinter factions, what they bought from the Foxes at that time (3132-3135?), what they salvaged from regular Republic forces and invading Liaos before the last stragglers joined Rikkard to invade Marik. THEN they destroyed the Marik-Stewart Commonwealth's defending regiment while 'buying' more Fox support, expanded the Protectorate which means faced occasional raids from randos, faced Trials of Possession against the Crusader Wolves in the early to mid 40s, and finally fought several rounds with the Regulan Hussars (broke 2 regiments?). Their touman is separate from the FWLM and I would be surprised if they imported equipment from the rest of the League, and instead would be considered a net exporter of military equipment as a province.
If you are going to reference a Nova Cat era on the MUL you would be better off looking at Jihad or Early Republic as a source since that is when the factional split occurred and while they did trade in later eras it would not weight towards that list.