Who is your escrow?
No need to escrow. I already received the funds from the client. I would be responsible for the payment to the participants.
Of course you need an escrow! You do not have enough trust to trust your words.
Caution: The risk of not getting paid is very high!I have been on the Forum for quite long time having more activity than you. So you need not worry about payment risk. I don't think it's that big campaign which needs an escrow to run. Rest everything will be clear when participants get paid.