Good question, TP. It's close.
The main reason to take Simmons over Griffin is because he fits our timeline better. Blake doesn't put us over the top the next couple years, what with the trio of GSW, SAS, and the Cavs. Then he becomes a free agent, and he could leave, or his play could start to decline (he'll be 29 at that point).
So if Simmons was guaranteed to be as good as Griffin, you keep Simmons for sure. But he's not. He looks like he'll be really good, but there are still questions about his shooting and defense, and it's not clear that he can be as dominant in the post and the PnR as Griffin is to make up for it.
By the way, Griffin is actually a compelling upside comp for Simmons. If he can be like Griffin with better passing ability and worse size, that's a really valuable player.
So the question becomes, do you make the trade given that Simmons becomes very good but not quite as good as Griffin? That I think is a really tough question. I lean toward yes.
The last question about DeAndre Jordan I think is a clear no. Jordan is a great player, but he has such glaring flaws (FT shooting, spacing on offense, maturity) that I wouldn't consider giving up the Nets pick for him, especially if the Nets are bad enough this year for us to get the #1 pick. Then if you're adding AB and KO on top of it, there's no question - bad deal.