For war priority, probably Skadi since she’s a beast in rush war and minion war.
I personally would also consider Athena since she’s the best defense-down hero in game. If you push for high scores on legendary mode of challenge events, mythic titans, or even regular red titans, Athena will be a boon. C. Magni can give -34% def but Athena can get down to -65% def.
I would probably ascend them in this order of priority:
You already have Alasie and C.Magni for snipers which is why I think Alice isn’t as high of a priority (although another fast speed sniper is always good). IIRC, base Alasie also does more dmg than Alice.