The white screen definitely sounds like an AJAX problem which could also explain the ordering issue. Sorry that you are not having a lot of luck of late!
So – is this also a new symptom (the white screen response)? Something must have changed somewhere. My guess is that jQuery is stopped which explains it all.
On a related note – I have made another attempt to install JetPack but for some reason it dislikes my XMLRPC response even though it is responding correctly. I assume this is because i am running a local test system. If I run Jetpack in local development mode I can’t turn on the stats so either way it stymies me!
As far as I can tell however, the problem may lie in the use of the underscore.js library which clearly something is trying to to use but is probably not being loaded at all. Just a theory…