First off thanks for your comments! And yes... exposition definitely goes overboard which is something I'm working on improving in Episode 2. That said, this is planned out to be a very long series (currently planning 3 seasons) and there are things being setup now that won't pay off until season 3, but I have to start slowly feeding information to the players.
Funny enough, the first version that my reviewers received had even more information that was removed to clarify things a bit. I'm working on a way to provide more details on the world, in a way that is easily accessible for those who are interested, but just as easy to ignore for those who don't. This additional information would be limited to things that the MC would actually know, so there won't be any spoilers.
As for the models.. I cannot take credit for those as they are the work of the amazing ND3D. As mentioned in another response, most of the characters are within their statistical height. I say most, as there are two that aren't for reasons that will be explained in the future.
Heh... there is definitely no plot hole but there ARE unanswered questions. I think it's easy enough to figure out how the trio (nice phrasing btw!) were infected, but the other two are a definite mystery in this episode. Episode 2 will start to explore these questions, but don't expect quick or easy answers to everything 
First off, the trio + MC were always going to happen, even without PGI. We'll start seeing more about the family's backstory via additional flashbacks in the future, but even in this episode you can see that Tracy has spent a LOT of time preparing (some would say grooming?) the girls.
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As for PGI-257... all I can say is that nobody has said that Frank and his daughters have PGI-257. All we know so far is that it acts VERY different from PGI-255.
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Another thing to point out is this line which in hindsight I could have made a little more obvious.
MC Thinking
I can't tell her the whole truth.. not until I know more about what's going on, but a little bit of the truth goes a long way.
When he says the whole truth, he means the the mind-control/psychological aspects. After she reveals the 'family' phrase, he's willing to reveal a bit more, but for the most part he keeps things close to his chest. His only goal in life is to protect his family and while Jasmine may eventually be family, she hasn't gotten to that point yet. Even with the 'family' code phrase that Tracy gave her.