iCloud, Photostream and 8 iOS devices…I need some advice

OK, we are loyal, happy and completely Apple fans in our house. 4 iPhone 5S, 2 iPad minis and 2 iPads, 1 MacBook Pro and an iMac. We live and breathe the apps and synching capabilities of all the devices to keep our lives in-synch...or at least as a busy family of four can.

My issue is this: with the phones and ipads all on iCloud, we totally blow through the basic storage plan on iCloud. Now, I am not opposed to buying more space if I need to, but my question and need for help is this:

I have a son who loves to play with the video software, etc and it eats up our strage. My 16 year old loves to takes pics from Pinterest and text to her girlfirends, so that eats into our space. My wife and I are both professionals and we have a tendancy to snap pics of docs, etc and share with co-workers, etc during work texting, etc.

What I am getting at, we all love the fact that when mom snaps a birthday pic at a party, we can all see it later, but 3 of us also don't care anything about the cute puppy pic that was on Pinterest or the latest special effects video that the boy made, etc.

HELP! We are out of space and the iCloud machine says we cannot back up.

If I turn off Photostream, we will miss the sharing of the pics...I get that. But what if we wanted to keep everything backed up (Photostream) and have it dump into iPhoto on the iMac but turned off Camera Roll from iCloud...would that at least keep the camera roll pics from iCloud and also provide us some more space on the individual devices without losing the pics (because they have been dumped onto iPhoto on the iMac?)

I think I have thoroughly confused myself...the family is certainly stumped and now I might have even confused you good people.

please advise and ask any questions you feel is necessary and/or make any recommendations. PLEASE use small words, large pictures and write in crayon if possible...my brain is about to explode!

Sproles