SBS 2011 Exchange Update to SP3 prior to Exchange 2016 Migration

Hi Team!  We're mid migration between SBS 2011 and SErver 2016. Issue is Exchange specifically.  Following the install path outlined everywhere, Exchange 2010 needed to be SP3, RU 11.  I'll save granular details, but short answer is that took, but the EMC and Shell failed to come up.  I'm seeing lots of EID 2280's and 5139's.  Have done the re-register of exppw.dll, I've reinstalled and moved up to CU 29.  The error's when you open the EMC suggest easy paths to fix. Nothing's working.

Now, the detail that's eating at me..  the error on the 2016 install side that stopped the process was a complaint about exchange 2003 in the environment.  The SBS2011 server started way back as a seperate sbs2003 server and thus old exchange 2003.  It was migrated to SBS 2011 / exchange 2010.   Obviously something hanging out in there.  But on paper shouldn't be the cause of the exchange failure behavior across the network (users can't open outlook with out prompt, owa is sketchy as I'm trying to fix, phones won't connect, emc won't open...)

So, all this said, the bottom line is I've run Exchange SP3 to RU 29 and it's pretty unhappy.  Any guidance is appreciated.
JP