Story-wise, the Great Beings made the first, then the Matoran created more mechanically, while the Agori...did some things. Reality-wise, the set designers come up with an idea, design the set, send it to the parts makers to make them, copy them, and distribute them, where they end up in your lucky hands.
Lego.
Bionicles Cannot Eat Anything.
bionicles are supposed to end in 2011
You will get some bionicles on ebay but they are second handed
Only the Agori Bionicles reproduce, but it is never stated in canon how they do so. It is commonly assumed that they just build more. There are also some that theorize that the Matoran reproduce, or there would be no need for the gender roles.
go to http://www.toywiz.us/search.php but be ready to spend more than $130 on bionicles.
Each month ibionicle gives away free Bionicles. Check them out at www.ibionicle.com
Unknown
Many
Yes
bohrok
Lego Company