Thats what we assumed on Asha. However its always good to check on a new game to see if thats how it really works.
Yes, so long as you're still at the right step to initiate a triggered ability - it doesn't matter whether the card was blank or not (or not in hand yet - maybe you just drew the We do Not Sow with Great Kraken) while its triggering condition was being met - you can still use it. Note that while they all meet their triggering condition (winning a challenge unopposed), each one happens in turn (And is resolved fully in turn) - so these are NOT considered simultaneous.
szczudel is correct on the second count too - they are simultaneous abilities because they both happen at the same timing step, and aren't triggered. In that case, as per RR p16 "Priority of Simultaneous Resolution":
xxIf the resolution of two or more when revealed abilities, delayed effects, or forced abilities would resolve at the same time, the first player decides the order in which the abilities resolve, regardless of who controls the cards bearing the conflicting abilities.
xxIf two or more constant abilities and/or lasting effects cannot be applied simultaneously, the first player determines the order in which the constant abilities are applied.