iCloud Drive over multiple Apple ID's

I've got a variety of apple devices and am trying to work out the best way to keep documents in sync across them all. The ideal solution would be to use iCloud drive but my macbook and iPhone are on one apple ID and my wife's iPad and iPhone are on another. I'd like to keep them on separate apple ID's as we have different contact groups and don't want to see iCloud tabs for each other, etc. Plus backing up 4 devices to one iCloud account won't leave much space for anything else and when Microsoft give out 30gb, google give out 10gb the 5gb iCloud allowance is pretty poor.

At the moment we use google drive to store all our documents and just access this on our devices via the drive app. I'd really like to switch to using iCloud drive as it'll mean I can use iWork more than office but there just doesn't seem to be a way to keep documents in sync across multiple apple ID's. Google drive also doesn't cater for iWork file formats so I can't simply save everything in there and just copy over to iCloud drive.

Does anyone have any bright ideas? Are there any third party iOS apps that will let you access items stored in icloud drive? I'd also thought about trying to use automator or applescript to copy a few select documents over to iCloud drive and convert to the iWork formats but I'm quite new to all that so not very sure where to start.

Thanks in advance for any suggestions.

I've noticed today that microsoft have amended their office apps to allow access to iCloud drive on iPhone. Just been playing around with it and its quite good.

I've been thinking that to resolve my issues in my original post I could move all the contents of my google drive folder on my macbook over to the iCloud drive folder. If I kept the sync going to google too then I'd have all my docs available on iCloud drive for my apple devices but would also be able to login to google drive on my wife devices too - has anyone sync'd the iCloud drive folder with google drive for mac?