"For a starter motor, as battery voltage drops, the max current potential that can be developed by the stater motor goes down." YES
" A starter will not draw more current with a lower voltage than it will with a higher voltage" YES
"A starter WILL draw more amps at a lower voltage. Sometimes much more. This is the double whamy of winter starting... decreased battery voltage and thickened oil. "
This is true weather its AC or DC if the motor is "universal wound" and has brushes." NO
The joy of the brushed motor is feeding it lower voltage simply makes it weaker, and does not cause it to draw more amps .
This is the reason starters have brushes , and are not wounld like air conditoners , where when the voltage drops the watts remain the same by drawing more amps , till the white smoke escapes.
At tag sales I am always on the lookout for items with brushed motors.
Things like chain saws that may be on a 400 ft extension cord don't mind a bit.
Even circular saws can be found that work without overheating on a cruddy dock, a poor inverter or a too small noisemaker.