First of all, far slash isn't even in range of her counters. Second, rerere isn't a poke. Third, why are you throwing items when youre open?
A major part of Faust's game is to keep them in an area where you can reach them but they can't reach you. Let the items do their job of making them bring their game to you. Learn to use Faust's anti-airs, push them away if theyre on the ground.
As for Baiken being hard to guard break, don't worry about it. The majority of your damage will come from anti-air combos, and converting random item hits into combos. If she tries to reach you from the ground, she won't get close enough to hit you before you're in range to poke or sweep her. Always remember Baiken is light and low def, so sweeps should always go into pogo then GMW and/or RC air combo. It deals enough damage from that simple setup that they'll try to find other ways of attack instead of risking of getting hit by another. Overall, the normal Faust gameplay works fine vs. Baiken - the only thing you'd need to change is your blockstrings. Limit them to 1 hit pokes and don't try to penetrate her guard by long blockstrings.
For Millia, Deuce is correct. Millia beats Faust normals air and ground. You can't even bait Millia's anti-air to safely land, and Millia beats Faust anti-air too. Your best strategy is to guard her pin once its out and don't let her have it. Once she has no pin your anti-airs will work better, but still not as good. On the ground you're still not much of a winner. Her pokes beat yours and thats basically it. A couple of counters work, doing a jump 2K just before she reaches you and attacks will avoid low pokes and kicks, netting a good CH stun into combo a > sweep pogo > gmw. But this gets beaten by around half of what Millia will attack with (like 6P), so you get a 50% chance to beat her attack if you're just completely guessing. To beat the other half of her normals, use 2S. While 2S is a good counter to her attacks, its not at all safe to spam. It has a long RE so if you whiff you're in trouble. But you pretty much have no choice here. Well at least Millia is a low def light.
Vs. Jam, the normal gameplay style works fine. All you need to watch out for are charged dragon kicks from halfscreen+. These are quick and have a lot of priority. Jam is another low def light so make sure you abuse sweep > pogo. Her normals are short ranged and she is a limb-only character - meaning pushing her out of her range is pretty easy. She doesn't stand, run or attack in a low hitbox so you don't have to worry about height whiffing moves. (For Baiken and Millia you have to compensate since they're small and duck most of your moves.)