just get a beater car.

 

All you'll need to worry about is the clutch assembly prematurely wearing out, and maybe some synchromesh grind - but then again if you can successfully teach her to use the clutch correctly that shouldn't be a problem. Also if she's easy on moving the stick and not forcing it into the gates, that should be fine on the synchros too.

Break every gearshift down into steps and make it a routine for her, so she can rely on her muscle memory taking over in time. The key word is confidence - she'll definitely stall a few times, but knowing what to do to avoid it will come with more seat time. I assume most of us were pretty clueless with manual gearboxes at the start too; we weren't exactly genetically programmed to change gears.

As for full clutch engagement:
The only times I "ride" the clutch are when in first and reverse and crawling, because you do have to balance the clutch and throttle input in slow-speed situations. Otherwise my foot is clear of the left pedal.