One of the things I've been digging into for expanding this is the information on production of military hardware - while many factories may be assumed lost to the Succession Wars and have simply not been mentioned, changes to borders and priorities can lead to odd patterns. (Also, Achernar BattleMechs, arguably the 'Mech manufacturer for the AFFS is listed in some sources as having moved to New Avalon from Achernar in the Terran Hegemony after the fall of the Star League. In which case it's a bit odd they built the Battleax and Hammerhands. Someone didn't fact check somewhere, I think).
What I've worked out so far for production in the Federated Suns (including some AU elements) would be as follows:
Achernar BattleMechs of New Avalon: Wasp, Phoenix Hawk, Dervish, Battleax, Hammerhands
Achernar BattleMechs of Point Barrow: Crab, Enfield, Starslayer
Corean Enterprises of New Avalon: Valkyrie (from 2770s), Kynigos wheeled APC
General Motors of Bonneau: Blackjack (from 2770s), Cestus (from 2780s), Nightstar (from 2780s)
General Motors of Kathil: Blackjack, Cestus, Marauder, Maelstrom (from 2770s), Dragon Fire (from 2770s), Nightstar (from 2770)
General Motors of Salem: 'generic' APCs
Jalastar Aerospace: Manticore heavy tank, Sabre, Centurion
Jerricho Industries of Robinson: Swordsman, Cazador hover APC
Johnston Industries of Barstow: Culverin weapon carrier, Carronade artillery vehicle
Johnston Industries of Kirklin: Merkava Mk VIII heavy tank (from 2760s), Merkava Mk VIII(P) heavy tank (from 2770s), Alacorn Mk III & Mk IV heavy tank (from 2760s), Alacorn Mk VI heavy tank (from 2770s)
Johnston Industries of New Syrtis: Chasseur tracked APC
Kallon Industries of Talon: Swordsman, Griffin, Rifleman, JagerMech (from 2790s*), Partisan air defense tank (from 2770s*)
Kallon Industries of Minette: Partisan air defense tank (from 2770s*)
Lycomb IntroTechnologies Inc of Demeter: Stuka
Lycomb-Davion IntroTech of New Avalon: Stuka (from 2770s)
Norse BattleMech Works of Marduk: Wolverine
Norse BattleMech Works of Andalusia: Wolverine (from 2770s)
StarCorps of Crofton: Warhammer, Longbow, Emperor
Veridian Dynamics of Torrence: Tiger medium tank
Wangker Aerospace of Axton: Tomahawk, Corsair (from 2770s), Thunderbird
Wangker Aerospace of Andalusia: Tomahawk (from 2780s), Corsair (2780s)
* historically the JagerMech was from the 2770s and the Partisan from the 2790s. In hindsight, I think Hanse would advise reversing the priorities on the two.