Ok first if you buy it in mono mode ie no second seat.
: bassinet, seat, rain cover, no sun cover unfortunately.
In duo mode:
One bassinet, two seats, two rain covers.
Twin mode is the same as duo except you get two bassinets instead of one.
Nothing can be interchange between the cammy and the donkey.
You can get a skateboard for the donkey so you can transport up to 3 kids. It's the normal bugaboo board then you need to buy an attachment so the board fits on.
It is quick and easy to change colors. Extra hoods are about $80. So I've got a few colors