My Simplified Suggestion for the Faithful And Discreet Slave (Matthew 24:45-51, Luke 12:40-48):
It's really just a simple parable showing that Jesus will reward the leaders of each Congregation / Church who remain faithful and discreet in caring for their flocks, and that He will punish the wicked leaders.
Nothing more, nothing less.
This parable is exactly like the messages Jesus delivered to the 7 Congregations in Revelation 2:1 through 3:22.
There is nothing in the Bible that links the Faithful and Discreet Slave to anything else besides the leaders of Congregations.
Plus, since this is definitely a parable/illustration, the Governing Body now says we should not be looking for any special complicated antitypical fulfillments or giving explanations for every detail of the parable.