Yes, The Mighty Rages adds -everything- to the other rages. The other rages gives the Hp, Saves, DMG, To Hit etc to the massive hp the Might Rage gives and the Vampiric Regen too. It even wors alongside Thunder and Terrifying Rages.
Though... The +3 Universal Saves that Mighty Rage should add is still bugged to this day...
I have reported it a long time ago. I do not know much, but I think it is hard coded to fix and may be on low priority to fix. Devs will correct me if I am wrong though.
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Wilfire Strongfeet (Tight pants)
Adela Griffonheart (Poke)
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