Users will be Paid on their fastdice wallets and they could cashout from there directly to their respective wallets
This is a very bad way to handle payouts. In the event that someone claims they did not receive their payout, or that they are unable to withdraw their earnings, then it would be impossible for you to prove that you actually paid them.
If you actually plan on paying participants then I would suggest that you pay directly to a BTC address of the participants choice.
As mentioned previously numerous times, you should have funds escrowed to protect participants of your campaign. Having funds guaranteed by escrow will help you attract higher quality participants, and will show that you are not simply looking for free advertising. I understand that you have 25
BTC at 13qRqYA8hwrWDiAyvqYcTcijdGxpvMxGvi however, your lack of prior trust around here makes it so there is no guarantee that you will actually spend those funds
edit: I am also curious as to why exactly you withdrew BTC directly from LocalBitcoins in order to fund the address that is going to pay participants