K.C.
Of the two, I definitely prefer Mila Renee. I dislike the name Farrah a lot and I also don't think that Farrah Lark sounds very good.
I think enough people will be familiar with the name Mila that it will get pronounced correctly at least half of the time, though others will definitely call her Myla. If you go with that name, definitely spell it Mila. DO NOT spell it Meela.
If you want one that ends in A, I also like Anna, Carissa, Emma, Hannah, and Sarah (I like them all more than Mila). I think Anna, Emma, and Hannah all work with Renee.