2) When you have damaged a bulb, how much damage is "okay"? How
much can get lopped of, and the thing will probably grow next spring
anyway?

Ted
As long as there is part of the basal plate attached to the piece, it should
grow.
Of course, the larger the part of the plate, the more likely it will grow and
bloom.

The basal plate is the flat part at the bottom of the bulb where the roots will
emerge.
I let any cut pieces dry out for a day or so and callous over before
replanting.

Emilie
NorCal