i swear by SAS for spell icon placement on the action bars, btw.

Backing up a specific toon's Macros and Keybindings

Macros
for per-character macros - what u need is to backup the file: World of Warcraft\WTF\Account\[list=1]\[list=1]\macros-cache.txt
then move this file to its proper post-transfer location: World of Warcraft\WTF\Account\<new account name>\<new char name>\macros-cache.txt

if you want to backup the account-wide macros as well, backup the file: World of Warcraft\WTF\Account\[list=1]\macros-cache.txt
then move it to its proper post-transfer location: World of Warcraft\WTF\Account\<new account name>\macros-cache.txt

Keybindings
for per-character keybindings: World of Warcraft\WTF\Account\[list=1]\[list=1]\bindings-cache.wtf
then move it to its proper post-transfer location: World of Warcraft\WTF\Account\<new account name>\<new char name>\bindings-cache.wtf

as for account-wide keybindings, what you need is the file: World of Warcraft\WTF\Account\[list=1]\bindings-cache.wtf
then move it to its proper post-transfer location: World of Warcraft\WTF\Account\<new account name>\bindings-cache.wtf

Action Bar
as for your "old" action bar setup and placement, i suggest using Bartender4 to save the current profile and copy the file World of Warcraft\WTF\Account\[list=1]\Saved Variables\Bartender4.lua to its new location \<new account name>\Saved Variables\Bartender4.lua

Spells
and to copy your "old" button arrangement or spell/skill placement, i think they stay the same. but if not, as was mentioned earlier, Simple Action Sets (SAS) will allow you to save your old button config into a profile in-game then move the file World of Warcraft\WTF\Account\[list=1]\Saved Variables\SimpleActionSets.lua into its post-transfer location \<new account name>\Saved Variables\SimpleActionSets.lua

hope this helps.