Morris Minor Owners Club

Hi
Looking at converting my daughters Minor to alternator, with a kit from Bull Motif or similar.
My question is, will I need to change/convert the starter motor? (car is pos earth)

.. and what about the heater fan?

No

Nor the wiper motor!
You will need to swop the connections on the coil - and clean/reset the points in the dizzy and the fuel pump.