Rtron:
Minor thing really but still bugs me. Humans have only been in the galactic community for less than thirty years, and since the Legion is far older than that, the name of its founder cannot've been suggested by a human before Tevura arrived, as humans were still busy colonising and fighting over America.... (roughly).
It is somewhat amusing that you make this (common) mistake despite one of your characters later fully accounting for the fact...
Also, Asari not only live longer than humans but take a little longer to mature I believe, though the wiki is annoyingly lacking in specifics and its been a while since I've chatted to Liara... Anyway, the point, Morinth was discovered to be Ardat Yakshi at the age of 40. I think 16 is slightly more like a child for an Asari, and adding a few years onto her age before her experimenting might be a good idea...
Aside from this, this is a remarkably well crafted Ardat Yakshi character. You do yourself credit Rtron.
My only issue with Tasi is why exactly there would be a mutiny on a Quarian ship. Sure, they have disagreements, but those disagreements are almost never solved with violence, as Quarians tend towards solving things through debate instead of killing, more so now that their population is so limited.
Other possibilities to replicate that situation could include the ship being attacked from outside, though I leave it to you as to the specifics.
Kalros is interesting. My issue with her is again in the early part of her life, in that Tuchanka doesn't actually have a spaceport per-se. The place Shepard lands is merely the silo entrance to Urdnots settlement, not an official spaceport, as Tuchanka isn't exactly a hot destination for trade or tourism. Plenty of Krogan do leave their homeworld though so I assume there are a few spots that could be considered analagous to a spaceport, likely the more well established clan settlements. So i guess not so much of an issue as clarification, she'd've had to go to another clan most likely, and been very lucky.
Dave seems mostly alright. I like how he was utterly annihilated by the Turian fleet. They tend to do that.
I don't think he'd be the most famous... Terminus is large and has a lot of pirates after all, though some fame is alright.