The title is probably clear enough, but i'll make some examples:
1) flat bonuses: strenght modifier, power attack bonus, smite evil... will they be multiplied?
2) precision damage like a sneak attack: multiply or not?
3) extra dice from weapon special abilities: bane, flaming... multiply? No multiply?
4) extra dice from other items' special abilities: rhino hide, mammoth hide... Yes or no?
6) Do you have some other interesting example i could be missing?
No, despite the fact that they're written as x2 or x3, what you're really doing is adding. So a lance gains an additional 2x the regular damage, which would normally be 1x+2x=3x for a crit, but in the case of spirited charge would be 3x+2x=5x regular damage. A greatsword crit would do 3x, a greataxe 4x, a scythe 5x with spirited charge.
|Bob Bob Bob|
Does a crit then multiply it even further?So a Lance is X9 on a crit, A greatsword is X4 on a crit, a greataxe is X6 on a crit, and a scythe is a X8 on a crit?
Yes, but not like that. The way you do two multipliers is by making both work off of the base. A lance crit would be x6 (effectively). Since it's base*3 (crit)+base*3 (spirited charge). Greatsword would be x4 (x2+x2) and scythe would be x6 (x2+x4).