Unless iCloud somehow holds your only backup (and I don’t think this is normally the case), it will minimally affect you.
This tutorial to optimize iCloud for your iPhone will give you an idea of what’s there.
http://9to5mac.com/2014/08/31/ios-7-how-to-manage-your-icloud-account-storage-space/
I don’t know if turning these off will immediately delete your data on iCloud, sadly. Also, I don’t know if any credit card information in Passbook is in plaintext in iCloud.
Pinging Swordmaker for more...
Thanks for the ping. I was out of town. It’s not what it seems or claimed. See my ping post.