M.L.
Brittney is a very pretty name. Think of a name with a vowel at the end so the first name glides into the second - such as Marla or even M.. The names would sound well in either order.
Commenting about an earlier post - I'm rather a "grammar police" sort of person myself, but most of the mamas who post here do their posting in seconds, not minutes - the seconds that happen between feeding the baby and rescuing the puppy from the toddler.