I don't recall a program quite as bad as this. I've seen a few in 40 years as a computer professional, but 10 running processes plus multiple instances of another? Even without MCF running, I get high cpu usage from all this bloat. I get that in a professional environment, people might dedicate a machine to do nothing but editing, but what about the rest of us? Here is the list of what I have found in just a casual quick check:

Avid Application Manager

Avid Application Manager Helper

Avid Editor DB Engine

Avid Editor DB Engine (again! the service?)

Avid Editor PSE

Avid Editor PSE (again!)

Avid Editor Transcode Status

Avid Editor Transcode Status (again! Editor Broker service?)

Avid HUB Service

Avid Transport Client

About 120MB of RAM taken up in the background  and 8-10% of my CPU when MCF isn't even running and I won't use it but a few times a year. On top of that, it launches multiple instances of "QtWebEngineProcess.exe". What are you using this last item for? What is the database engine, SQL? 

Can anyone tell me which of these things if any I can delete, or at least remove from startup? Any of the services that I can switch off and run as "manual"? I already have several database runtimes from Visual Studio and RAD Studio, do I need your database runtimes too? Do they have to run as services when I am not using them? Thank you.

When idle, these processes don't eat up a lot of resources, except a couple hundreds of MB of RAM as you mention (which isn't very significant if your system has the recommended amount of RAM: as a very minimum 8 GB). You can try setting the offending Services startup to "manual", then create the following .cmd files to "Run as administrator" when you need to work with MC:

  net start "Avid Editor Db Engine"
  net start "Avid Editor Broker"
  net start "Avid Editor Transcode Status"

And when you're done with MC and need to recover that small bit of RAM:

  net stop "Avid Editor Transcode Status"
  net stop "Avid Editor Broker"
  net stop "Avid Editor Db Engine"