Yes the order of rules is very important.
The game does also tell you that:
https://imgur.com/ZC2y2Zy
I would also suggest checking out my basic guide about loot filters, in the very first paragraphs i do explain it by an example, that actually has a huge impact by just swapping 2 rules.
It depends, generally class-specific affixes are a lot more rare than regular affixes, so having my class specific recolor rule enabled would already help with collecting those more rare affixes for other classes already.
Other than class-specific affixes on body armour, helmet and relics (and also rogue exclusive bows & quivers) all classes share the same affix pools.
So if you enable my recolour rule for every affixes of Tier >=4 or total affix tier count of >=15 yo uwill passively collect alot of stuff that will be usefull for all kidns of builds and classes.