There's plenty of ways you can use the counterparts for good or at least neutral.
Bloodcraft could be used for healing or fixing disablities like a broken spine but fusing an injured person with a healthy animal. Old or injured warriors could volunteer to be fused with whatever to keep fighting. It could be seen as a sign of status in whatever culture to be fused with some beast. Instead of tradtional technology they could be based around bio-tech, fusing creatures to serve their purposes instead of building machines. Etc and so on.
The pure destruction of Dragonfire can be useful too. Say there's a cave in, or a building collapse. If you can just get rid of those rocks and debris think of how many lives you could save. And of course, like the old saying goes, the best defense is a good offense, a barrage of arrows is useless if they get burned to nothing before they can hit, etc.
The third one is a bit harder, but I can easily see it being used as a weapon of honor among some culture. Duels betwen users of the ability without the risk of death, etc. It'd be also more useful for training, I mean, you can't spar with somebody else if you kill / knock them out in one shot, and what if you need to disipline without incapacitating? Not even prisoners but say cattle? A slight shock would help in keeping a herd in check.
EDIT: Basically, what I'm trying to say, even if "corrupted" it's still what you do with a thing that's evil and not the thing itself.
EDIT again: But again, it's your story so if you want any use of those magics to automatically condemn your soul for all eternity that's your choice.