I like Ehrman. I think Jesus had, before the Resurrection, no clear idea of who/what he was and that what Ehrman shows is how the early church not invented but discovered the divinity of Jesus.
Calvin was totally opposed to this kind of theology. I presume you're referencing to Weber; but if you read The Protestant Ethic closely, he didn't speak about mainstream Calvinism of his time, but German puritanism, which was opposed by mainstream Calvinism.
There are many possible points of disagreement within Christianity because, like it or not, the Bible is unclear and even contradicts itself on many subjects (and this is a Christian saying this). But prosperity theology is so clearly the opposite of everything in the Bible that any self-respecting evangelical should ostracize it. That they don't is the proof that the gospel is not what many evangelicals are interested in.
Jlai.lu is more a francophone than strictly French instance, even if as far as I know most admins are French.