Backup each WTF folder before you start messing with them. I back mine up frequently anyway because I'm paranoid (addons can easily be reinstalled, but the hours spent doing set up can't).

Video and Audio settings are stored in: WoW\WTF\Config.wtf

Account-wide macros are stored in: WoW\WTF\Account\USERNAME\macros-cache.txt
Character-specific macros are stored in: WoW\WTF\Account\USERNAME\REALMNAME\CHARACTERNAME\m acros-cache.txt

Account-wide key bindings are stored in: WoW\WTF\Account\USERNAME\bindings-cache.wtf
Character-specific key bindings are stored in: WoW\WTF\Account\USERNAME\REALMNAME\CHARACTERNAME\b indings-cache.wtf

As for copying the addon settings between toons, sometimes it "just works" but other times it won't, due to the way the settings are stored. This will vary from addon to addon.

AddOns can save their variables in either WoW\WTF\Account\SavedVariables\ADDONNAME.lua or WoW\WTF\Account\USERNAME\REALMNAME\CHARACTERNAME\S avedVariables\ADDONNAME.lua. But it is up to the addon author which one they use. Several addons will store character-specific data in the account-wide saved variable file. In this case you can, if you are careful, edit the lua file directly to change character names, or better yet, use the addons built in functionality to reuse the settings from one toon for another toon (which presumably is the reason they are stored account-wide instead of character-specific in the first place).