Re: Dealing with sudden fear
IMHO, it sound like you might be referring to what I think of as the fight, flight, or freeze reaction to the startle reflex. (I tend to save fear for a deeper my unconsciously cognitive process.)
Denzel Washington was in a movie (Man of Fire?) where he trains a young girl not to freeze at the starter pistol of a swimming race. Rather than feezing, she learned to leap forward.
A simple beginning exercise would be to have nage wait for an attack (any attack), just before the uke makes physical contact have them shout "NOW!", signalling the nage to move into the technique (any technique). The point is to move into (irimi: enter) the fight/flow rather than freeze or flee from it.
In the long range you would have to raise the level of stress/fear/threat and spontaneity beyond what most dojos could tolerate. It also may require a rewriting of some long held core values and identifications.
BTW: are your people coming to Atlanta?