iCloud hanging constantly on iOS devices

Is this an icloud issue or an iOS issue?
Basically i have 2 iOS devices- an iPhone 6 and an iPad mini retina. Recently (since updating to 8.4.1) every app that connects to iCloud has started freezing, crashing or completely locking the device up.

Podcasts: crashes when pressing play or pause. sometimes locks the device up requiring a hard restart- both ipad and iphone

Music: crashes, plays without sound. both iPad and iPhone

App store: only allows for one app to be downloaded. After that when a download is initiated it hangs with the spinning circle icon until the device is restarted and the download is started again. both devices.

iBooks: simply doesn't open. Hangs on white screen until inevitable crash. both devices

Signing out and signing back into icloud: signs out fine, but hangs on sign in until restarted.

I haven't tested the full range of apple apps yet, but they seem to be the only ones affected. 3'rd party apps are all working fine.

I've tested these issues on 7 different wifi connections with 2 different iSP's + verizon LTE with the same results, so I know it's not just the internet being slow.

Has anyone else had this happen and found a solution? I've spent every evening over the last week chatting into Apple support and, following their instructions, restored both devices multiple times- both to backups and as a fresh factory reset. As soon as iCloud is connected things start acting strangely.

I’m about at my wit’s end here. I’ve been using my wife’s 6 patiently waiting for the 6s to come out since the battery in the refurb 5s apple care sent me only lasts a couple hours and the refurb’s serial number says it’s no longer eligible for repair service. I can’t really see waiting any more if I’m just going to continue having these issues and Apple itself seems unable to help resolve any of them even though it's affecting only their software.

Thanks! (sorry for the ranty-ness)