I’m a little confused about the mechanics of Amara’s skill tree.
If I’ve selected the main special from the brawler tree as active, do passive skills I’ve invested in from other trees also activate or do they only activate when the main special from their tree is selected?
Most passives can be used with any of the three action skills. A few ones are specific to certain action skills. This is mentioned in their descriptions. This applies to every character/class.
This is one of the things that sets Amara apart from the other Vault Hunters: their Augments all apply only to a particular Action Skill, so while you can take an Action Skill from a different tree than the one you’re investing in, all the Augments will be for that tree’s Action Skill. Amara can mix Action Skills and Augments, and for the most part, everything works together . If you’re willing to spend 5 points in the Mystical Assault tree, for example, you can have a Phaseslam that also heals you with no issues.