Question about Friends List

If someone send me a Friend Request and I accept it. If I remove them from my Friend list, will it remove from their end?

Will they still able to see my online status and know whenever I log on if they don't remove me from their end?

I accidentally accept friend list someone I shouldn't have.

Removing them does not remove yourself from their friends list.
They are still able to see your status, your location, send you mogmail, the works.