For anyone who may be thinking about going the 1a Auto mirror route that has factory EC mirrors, you can still use the EC glass, but it isn't a direct swap.

My initial plan was to overlay the two EC wires to the 1A harness, but the 1A mirrors use a different backing plate so the factory mirror glass won't fit. The fold motor 1A uses has the same bolt pattern on the mirror head side, but the bolt pattern is smaller on the door bracket. Because of this, you need to use the factory mirror head to retain EC and the 1A door bracket.

The 1A mirror fold motor and limit switch need to be depinned and moved to the OE mirror head. The 4 wires need to be connected to the factory plug (direct fit from 1A harness), and then the OE head bolted to the 1A base. Everything works fine and you still have OE mirror glass that is easier to replace if it ever breaks.