Glad you're enjoying it!
A296No, it's only counted as an attack action for the purposes of what talents you can add to it.Q296
I know this means one can apply something like a Berserker's Brutal Strike (and an exertion talent). Does this also mean one can apply Vital Strike (as for normal Attack Actions)?
A297 No. While class features like blended training, which gives you a pool of talents that can be spent on either, exist, those instances split a single pool, allowing a specific class or archetype to internally rebalance towards being more martial or more magical. Taking two pools from classes with complete and unique progressions is not something the systems are intended to accommodate and can skew the general flow and progression of character power significantly.Q297
If one gestalts between a SoM and SoP character (e.g. Sentinel | Incanter), can one use the talents gained from the martial class to take spell talents? Can one use the talents gained from the magic class to take martial talents?
That being said, it's gestalt, which means you're already deep into homebrew/house-rule territory, so ask your GM.