I don't think this will help everyone because there are clearly multiple problems here but this FINALLY worked for me:
Problem: I CAN log into iCloud using iCloud Control Panel from a user account that does NOT user folder re-direction (primarily for the ROAMING folder under user) but I could NOT log in using my standard account using Folder Redirection.
SOLUTION: iCloud CP seems to create several folders in the roaming profile folder (Cookies, Keychains, Logs, Preferences, SyncNotifier and Ubiquity).
1) Log into account that does not use folder redirection and log into iCloud Control Panel
2) Log out of account and log into standard account that does use folder redirection.
3) Open C:\Users\UserWithoutRedirection\AppData\Roaming\Apple Computer and move all folders to desktop
4) Locate where your UserWithRedirection stores its Roaming profile, mine is located at \\DomainController\User Profiles\UserWithRedirection\AppData\Roaming
5) Move the folders from the desktop to \\DomainController\User Profiles\UserWithRedirection\AppData\Roaming\Apple Computer. Don't delete any folders already there, just add new ones.
Voila! This worked for me. Good luck. Stupid Windows OS!