For bugaboo chameleon you can buy 'adapters' (£30ish) which clip on to the pram frame, then you can secure a maxi cosi car seat to the frame.
I don't know if thats possible for the bugaboo bee.
Baby vest -no legs, poppers on the crotch.
(they come in shortsleeve/longsleeve/sleeveless. but i only use short sleeve)
Baby grow and sleepsuits - all in one, sleeves and legs and feet.
Some dont have feet - socks are needed here.
They are quite handy when its hot or when baby starts walking, as feet on babygrows are a bit slippy.
In the summer Romper suits are all in ones, with shortleeves and short leglength (no feet!!).
My baby wears nappy, baby vest, babygrow/sleepsuit, cardigan, bib.
(he drools a lot and needs a bib, my first son rarely wore a bib)
when you do go shopping you will notice 'newborn' size and '0-3months' size.
Some people will say dont bother with newborn just go straight to 0-3.
it just depends on the size of your baby.
my first wore 'newborn' for a month (he was small), my second never wore 'newborn size'.
if you do decide on 'newborn size', just get a couple of things. remember they grow fast.
you can always get more if required when they are born.
oh and baby nail clippers are useful. both mine were born with really long nails and scratch themselves.
HTH