You said: "An orphan finder. That's primary."

I presume you mean orphan records, not orphans in the literal family sense. It is a bit clunky, but can be done.

1) Make a copy of your file.
2) In the copy, select a person.
3) Go to Extended Family Chart
4) Extend the number of generations to be a maximum number for both ancestors and descendants.

Go get a cup of coffee. This will take awhile, especially with 40,000 people. In fact, 40,000 people may crash FTM (ie out of memory)

5) After you get the report, right click in any blank space in the report and select "Delete all people in this chart"

You will be left with everyone in your file not related to the selected person by blood or marriage, or all orphan records.

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You said: "One button deletion of branches."

Well, it's actually two buttons:

1) Get all descendants in a branch you want deleted showing in a chart - ie descendant chart, or whatever.
2) Right click in a blank space in the report.
3) Select from the right click menu: "Delete everyone in this chart".

Be aware, that this selection process will not delete all of the peripheral relatives of a branch (ie parents of spouses, parents of in-laws, former spouses of former spouses, etc, etc.). It may very well add to the orphan records you refer to in your first question by leaving the peripheral relatives.

Using the Extended Family chart should pick up all peripheral relatives (if FTM does what it is supposed to do. Since it has been seen that the relationship calculator does not always pickup all relationships, that could be a problem.)