"How fast could arrangements for financing and supports be put in place?"
I don't know. I know time is running out. And it seems the two options discussed most are bombing and financial in the form of sanctions or an embargo. I don't know why we don't hear more about toppling this regime.
Nukes don't kill, people do. Get rid of this regime, and we won't have to worry about the nukes.
Iran does not need nuclear power they have an abundence of oil.