In this threat mission, many questions that need official (or argumented) responses :

LOT OF SPOILER!!!! by the way, all this section (campaign) is only spoiler

so:

A/ What occurs if my last elite stormtrooper is killed AND they're no more fire on the board?

event 1 trigger when last elite stormtrooper is removed (and start some damage for rebels)

event 2 trigger when they are no more elite tropper nor fire!!!

of course, the point is, if event 1 resolution (damage) wound the last healthy hero? and that triggers event 3 (when all heroes are wounded)

event 2, rebels win

event 3, imperial wins

not often, but to be sure

B/ by the way, this bane (influence points at the end of mission) trigger or not (cause bane must be discarded): what is the timing

Thanks a lot

For the former I would need to read the events. But if there are simultaneous triggers, and both are mission rules, the imperial player decides their order. (Page 2 of the RRG: Timing)

For the latter see thread with Paul's clarification: https://boardgamegeek.com/thread/1511170/constant-advantage-clarification