Though no-one has asked

I'll offer my justification for Jiraiya's posse (+Kakashi)
Naruto (and 2 BM clones) squares off against Madara while Jiraiya gathers chakra for senjutsu and summons ALL the toads (to counter Nagato's summons). Jiraiya's job later on will be to absorb Amaterasu if there is any and to engage avaiable targets in taijutsu, an area he is LETHAL in. Elder toads assist with the toad song thing.
Minato faces off against Nagato as his speed makes him a hard target for Nagato's single person techs (soul rip, even possibly ninjutsu absorb) and FTG counters Bansho Tennin, Shinra Tensei and Chibaku Tensei.
Kakashi at full health seems like he's roughly equal to Obito and can make a clone to fight him in both dimensions at once.
Konan uses her freakishly large bomb collection to take care of either Madara, Nagato or the Bijuu, but in this scenario takes care of the Bijuu.
Plus, Jiraiya isn't at his best if there are no LADIES to IMPRESS!