There is no need to reinstall the iOS on your devices, and no need to reconfigure them all. There is a simple and easy way to remove all the photos without having to transfer them all. See previous threads regarding the Image Capture utility.
iCloud backups contain everything you need to restore your device back to the way it was before you dived into that pool and discovered the iPhone was not waterproof. All settings, personal data (photos, media, emails and game settings) are stored in the iCloud backup. Anything that is in the cloud already, like your iTunes purchases and Apps are simply re-downloaded.
To see how big your iCloud backup is, Settings -> iCloud -> Storage -> Manage Storage. This will show how much space each device is using. Click on the device to see and manage which data is backed up to the cloud. Don't want (or don't want to pay for the extra space) to backup your photos? Turn it off.
As far as bandwidth being a commodity, the device will only backup when it is connected to WiFi, Plugged in to a power source, and locked (in standby). If you plug in your phone when you go to bed, that's all you need to do.
iCloud backup is all you ever need. Never plug in to backup your device ever again. Pay the $0.99 a month for 20GB (5GB is free) and have the peace of mind that all your devices can be fully restored to a new device, pictures and all.
Regarding your lost photos, check to see if you had enabled PhotoStreaming prior to wiping the devices. You may be pleasantly surprised to find they are all in the cloud.
iCloud: My Photo Stream FAQ