Creating a new character has no impact on any cooldowns. As long as they are under level 29, they won’t create a cooldown, unless you use a character service to change their name.
No, the 90 day cooldown is based on when the character service is performed.
It was ticking down from when the character service name change was performed.
No. The level one has no impact on any cooldown.
On day 90, to the minute from when the character service was used, the cooldown will expire and the name will be available to everyone on that realm, assuming you don’t have a character already claiming the name.
If you do, deleting that character, if it is under level 30, will free up the name making it available for use by any other account/user.