Check the battle_models_db file. It will tell you what animation the Musketeers use. Fire_by_rank has been removed, so maybe that's why they don't go to the back after they've shot.
D:\SEGA\Medieval 2 Total War\mods\Stainless_Steel_6\data -> export_descr_character_traits.txt
Search for "beyond".
Select the character when he's outside of town. Type this in the console -> remove_trait this TooOldToFight
I forget if you need quotes around the trait name.
Oh yeah, and delete the aging script. It's better for characters to age only six months a turn, that way you have them for longer. It won't work for your current campaign, but it will apply to future ones.
"frighten_foot" in the EDU -> "Frightens nearby enemy infantry" on the description card
"frighten_foot, frighten_mounted" in the EDU -> "Frightens nearby enemy" on the description card
I don't remember ever seeing "Frightens nearby enemy cavalry" anywhere, and I can't remember what it says on camels.