From this week's episode I think it is safe to say that Echo and Victor had been in the dollhouse together for some time, and have now included Sierra into their "clique", but from when we started watching he was away on his engagement with the Russian mob to deflect Paul Ballard. We didn't see him and Echo so that we could get the "big reveal" that he was on active. Unfortunately it wasn't much of a surprise to anyone who had read any of the pre-show hype about the characters.

As far as Dewitt and her boss, my guess is she is like the executive officer or manger and the boss is like president or chairman of the board of directors. She takes care of the day to day workings of the Dollhouse, following the directives of her boss(es). If you watched Angel, Dewitt is like Lilah or Lindsey and the boss is like one of the "senior partners" .

I've been thinking about the "memory wipes". I don't think that the memories are removed but that access to the memories are, sort of like amnesia. Maybe when a seemingly new experience is stored it is put into a place and the link established. But if there is a similar something already stored there, that previously stored memory is now accessible too. Anyway however it works, if the neurological pathways start to grow back then the active would start to remember. When they were first discussing Alpha's escape and killing spree they were quite surprised that he remembered his surgical skills from a former imprint.

If my theory is true, then the actives have quite a bit of stuff stored in their heads - their personality and experiences before they became actives, the imprints of personalities and experiences of people to give them skills, the experiences they have while in an engagement using those skills, and their time in the Dollhouse. If an active were to remember all those things they would probably go crazy trying to figure out who they were.

I really like this theory. I definitely think that the show is headed in that direction.
Another possibility would be that in the future, if Echo (and potentially the other actives) remember what's been put into their head for their engagements, instead of going insane because of all the different personalities, it could be a benefit for them. It would be like a library inside their heads of different resources they could use to fight Dollhouse. This could definitely be an alley Joss chooses to explore in future seasons.