Hi Carl, in the multimon menu, only the graphics changed between the previous preview release and this one; the implementation did not, so I can't think of a reason why you wouldn't be able to switch to 3 monitors now. The VMX log shows that it sees all 4 monitors, but the UI log says that Tools was not running.
Does this happen all the time? When it does happen, please look in Task Manager in the guest. Click "Show processes from all users" and look for processes named vmtoolsd.exe. There should be two copies running, one as System and one as your user. If you don't see two copies, then there could be a problem in Tools.
I can reproduce the bug about the "(current)" tag appearing next to the wrong layout, thanks for reporting that.