This is the $100,000 question, always.
For me, I have Red Hood+9 (took the mana node and def/HP route). Something I think people continually forget about her foxes is they resist mana reduction, which will only be more relevant the more that Vanaheim heroes are used (reduce enemies mana upon death).
An additional benefit with the fox minion is that it’s an endless HoT and not a buff or one time boost, so it “stacks” on top of any HoT you already have active.
Another member of my alliance has her as well and while I was having an existential crisis over whether to take her off my war defense he said “but Red Hood is life” and she has been for me since the day she came into my world.
You said it’s for war offense, so it goes back to the question posed by @AnomanderRick - I felt I needed to give my perspective on Red Hood, since she’s been a supremely protective Swiss army knife for me.