From the perspective of offensive, I don't think so. We're all adults and we know what we're getting into with stories, as long as everyone is legal and consenting. For humiliating, I can't say for certain, but I'd say the lesbian being forced to do oral and have sex with the husband would be pretty humiliating. However, as the winner, the wife should be involved. Kind of curious to see what you're planning as far as rules and style.