I followed the instructions on BAE4152000 July 1, 2018 (THANK YOU!!!!) and was able to get my OneDrive back working, and put the .exe shortcut on my desktop, as I'm not totally convinced that problems are over.
However, I'm thinking that there is more to this whole thing, as I still can't install the Feature Update 1803 on any of my three devices (desktop, laptop, Surface Pro 2, all running Malwarebytes Premium, btw.) I wish I'd kept track of all the error codes there, the last one being 0x80244018. I'm now trying the upgrade assistant. I'm wondering if MS is thinking those of us with Win7 or Win 8 computers upgraded to Win10 are now more trouble than they are worth to keep updated. Just thinking!