If I were to part with 3 le fabs...

What a hard decision...for me I would not part with any of these gorgeous beauties.

However if you really must to fund your Birkin, then keep the Plum and Geranium because they are rare and d/c-ed colours. Even though blue will be d/c-ed (?), I think black and white will be permanent so you can get them again later if you really wanted to.