Well if you have keyframes at the beginning of the first sequence, the would play ok if you play the sequences one by one, only when play eg. the 3th first and then the 2nd, it wouldn't work. But playing 1,2,3 would work since each sequence ends where the next one starts.
You could test it, I guess you can play a sequence with a speed of 0.001 or so, then check it's pose. If it's the correct start pose for this sequence (all bones), then the keys are there.
You could test it, I guess you can play a sequence with a speed of 0.001 or so, then check it's pose. If it's the correct start pose for this sequence (all bones), then the keys are there.