How many backups does iCloud/iPhone store on the computer?

My sister's iPhone 4S downloaded the most recent iOS (iOS 8. Something rather) without her telling her to do it at any point in time, and it's pretty well ruined her phone at this point. She can't upgrade or get a new phone for the next 4-5 months, and the phone with the iOS 8 has made it to where it's very close to being nothing more than a paperweight.

I'm wondering if anyone knows if multiple backups are stored on computers and if it's possible to select an older backup that has iOS 7 or 6 on it and apply it to the phone so it goes back to a software the phone can better handle?

Any help/feedback/advice is greatly appreciated.

How to completely wipe my iPhone even though it's broken?

The other day my phone stopped working, it has been broken for a while but now it's not working at all now. It won't turn on or anything. I need to wipe my phone completely and get my photos but I'm not sure how. Apparently you can do it on iCloud but I don't know haha someone help, please?

How to fix my iphone screen? - 1

Basically i dropped it and now it has annoying flashing horizontal grey lines all down the screen. Can i fix this myself? If not how much would it cost to fix?

IPhone case home button came off? Fix?

I recently got the iPhone 6, and as soon as I got it I ordered a case, I got one not many people really have heard of, but itnfinctions just as much as a lifeproof, but is cheaper. I've had the same problem with my lifeproof case on my 5s, but anyways to the problem…

I tested it when I opened it and nothing happened at first. I put my phone in and the next day I dropped it in the water for another test, well nothing happened after awhile. Then I noticed some water had gotten between the case and the screen. I took it out and looked, and notice the home button sticker was up a little bit. Is there anyway to fix this? Without shipping it off first? Because I don't want to go another couple weeks without a case, I thought about just putting a little
Bit of super glue under the part that is lifted up. Any help would be appreciated