No hards facts, I'm affraid...
My own personal belief is that plucking can weaken the hair such that it grows back finer or not at all.
My reason for thinking this is that I read once that you should never over-pluck your eyebrows. Sometimes people have plucked them thin but regretted it later in life when the fashion changed and they found their hair wouldn't grow back.
I've also heard tales of guys who've had their legs waxed for charity, and it never grew back! (In my book, waxing is just macro-plucking!)
... but having said that, I've also heard that plucking can stimulte the blood supply to the hair, making the hair grow stronger.
And my own thoughts are that birth control pills won't cause more hair growth. Body and facial hair is stimulated by testosterone. Unless you're on a progesterone only pill, the estrogen in the pill will help to counteract any effects of testosterone - so you might notice a small reduction in your hair, or a reduction in its strength and thickness.
Both of those are my own conclusion, though, from what I've been told about how it all works.
I'm more than happy to be put right!!