The Vasari guy shouldn't have too much of a problem.
His Kanrak Assailants, Fighter Squadrons, and Bomber Squadrons can continue fighting unaffected despite the Guardian's Repulsion ability, because the Assailant has very long range and because the strikecraft are not bothered by the Guardian's ability. They don't suffer much from the shield-bubble ability either because they are all armed with Phase Missiles that have a chance(depending on tech level) to penetrate through shields, ignore shield mitigation, and directly impact the enemy's hull(an Advent weakness, their hulls are flimsy).
The Vasari also have the Stilakus Subverter, which has an ability that reduces enemy shield mitigation by 10% and increases friendly Phase Missile penetration chance by 25%. The Subverter's second ability, Distortion Field, can outright disable a large chunk of the enemy fleet, except for capital ships and strikecraft. Distortion Field's only problem is that it costs a lot of antimatter in 1.09.
As for TEC, I don't know. Their LRM frigate should be able to outrange the Guardian's repulsion, but it'll take ages cutting down the Guardian's ass-whoopin' super-shields that have close to 2000 hp. Their strikecraft are also unaffected, but they suck in comparison to Vasari and Advent strike craft and will probably end up getting shredded by Advent fighters. But if you get a Level 6 Marza, you could use the Missile Barrage ability with the Incendiary Shells buff for a massive wiping of the floor with the enemy fleet, should you encounter the Guardian spam. The Akkan can also Ion Bolt individual targets to disable them. The Dunov's EMP Charge can also help nab the Guardian's shields and antimatter strengths.
