The Kage should be able to take them down. The 5 of them working as a team were able to inflict lethal damage to even Madara, several times and even though he probably wasn't fighting seriously, it's still a very impressive feat nonetheless.
The Kages showed they have good teamwork, for me this is a clear win for the Kages. Pein could take maybe 1 or 2 on his own but against 5 he's got no chance and Konan is useless. She'll be taken down easily by the Mizukage.
No, not as the 6 paths of Pain he couldn't. Sage Mode Naruto took out 5 of the paths by himself with relative ease. Then all you have is the deva path. Also this isn't a 1v1, it's a team battle and as was shown before, the Kages work really well as a team. If Oonoki and A team up again, even Deva path will struggle against that kind of speed and power.
Therefore, as a team, the Kages win this and Pain will struggle to take out any of them.
Konan's paper bomb jutsu that she used against Tobi required a lot of pre-prep and is not feasible in a regular fight. The Kage's are smart, they'll figure her weakness out in no time (provided Tsunade doesn't know it already) and then take her out with ease. She was never that great and was more of just Pain's partner more than anything else. Jiraiya took her out in no time at all.
Like I said, as a team the Kages will destroy Pain. They're able to work together as a team really well and like I said, when Oonoki and A do their combination attack, Pein's just not going to be able to respond.
Plus Pein's multivision will likely fail because the Mizukage can easily cover the field in mist. All in all, Pain has no chance against the 5 kages.
There's no prep. I don't see where you're going with this. Konan had set that jutsu up as a trap for Tobi whereas Tsunade always has been storing up her chakra. If they met in a random encouter, Tsunade would still have her chakra stores whereas Konan would not have set that trap up.
If the kages have the intel from Jiraiya, kages...
but if by "no prep" you mean they don't, i have to go with Pain
Other than Chibaku Tensei, Kages can easily destroy most of his bodies. Not all the individual bodies are kage level. At least most aren't.
And konan would struggle against more than two.