Each original owner of bitfointain has their own dividend address,
Don't think so. Bitfountain has 200'000 shares, and that's evenly divided in 15h6 and 1HgT address.
There are three addresses that are generally accepted as belonging to "Bitfountain".
232,520 shares, you aren't including
https://blockchain.info/address/1BnkEt2ceoVhnQVrqeAzigcroQ6MVyxFey