Would Crown Molding be a reliable way to cover up these corner cracks

Sure. But be prepared for some headaches trying to line up the edges. If
the house settled enough to crack the plaster, it also settled enough to be
out of square.

or should I be concerned that in a house like this, with known
shifting, crown molding could become an issue.

What shifting? This is an old house, it should be done settling by now. If
these are new cracks then you need to find out what's started moving.
Rectify that problem before you waste your time patching what's only going
to crack again.

I believe it was shifting between
my house and the ones attached on either side.

What're we talking about here? An actual town house or row house? I'm from
Baltimore originally so I know the difference. Calling those tiny little
houses "town houses" doesn't elevate them into the more solidly built as
'houses in town' for folks from the country. Row houses are often made from
inferior brick and rather lacking in engineering. If you've got problems
because of the houses next to you then your next call should be to a
structural engineer.

-Bill Kearney