alt source for "Sneak attack +1d6" , if so Check.
Rogue is Rogue, even if alternative Rogue, Check.
But the Rogue variant doesn't have a "Sneak attack"
progression at all, to be progressed by the feat.
Something more like a Bard 1 / Class X with the feat
that advances the bardic thingie.
normal Rogue 1 / Scout X / Fighter 2 or a major (dead-)fighter bloodline
is more what you have in mind.
However, I do recall some aguments that Tash + Monk
progression can happen without any Monk levels.
iirc Lycan pimped that, and SorO anti-pimped it.
If you're going that way, sure it works ; tho' disputed.