Jiraiya isn't guaranteed to die in this assault, I'd even say it's likely he survives in the cases where Akatsuki is defeated, and if he survives then he quite likely would have the political clout to pull it off in the future. If we want Hana in Leaf to be an option in the future if Jiraiya dies we need to act now.
And I'll repeat my previous statement: I don't want Hana in Leaf. Not now, not a year from now, maybe not ever. I fully expect that if Hana came to Leaf again she'd re-break Mari, and losing Mari is about five times worse for the Goketsu's social capabilities than not having Hana would be, and we can't stop Hana from doing whatever she wants. We've tried to have Hazou stand up to Hana and it hasn't worked, and I'm not going to wager everything on us succeeding this time.
edit: I also think that we probably can't get Hana's passport stamped at all right now. Her initial position was already politically challenging to pull off, seen as blatant nepotism and all that fun stuff. And the end result of that nepotism is that Hana got kicked out of Leaf within a couple weeks alongside a big list of demands for Mist to capitulate on. There is no way Ren has the political capital to approve this again, and I doubt Jiraiya has enough extra floating around to make the ends meet form his side.