The physical appearance of Lexi aside, the Shangri-La village of cult-like followers is a pretty decent place to have been done in just four months. Even if Lexi changed entirely in one day then it means that within 16 weeks she obtained followers, they found a location, and they not only cleaned it up but repaired the damage as well including a pretty nice water garden with landscaping. Unless they found a complete Home Depot store sealed off & pristine from before the invasion then I'd find it hard to believe that place got to where it is in just that time.
Then of course there are the re-education camps complete with DVD promotional videos to show the kids. Last season the kids were being harnessed, jump forward and now they are being indoctrinated by non-harnessed humans who have drank a little too much Kool-Aid.
Mason and the rest of the crew are in a prison ghetto and yet they've been able to form alliances, hold clandestine meetings, have a 'Ghost' folk hero emerge, and generally roam free to do almost whatever they want.
And how did a former doctor, Anne, become the rebel leader when just four months earlier she was on the verge of a mental breakdown with people fearing for her safety? After being abducted by the invading aliens, bearing an alien hybrid child, and then having some mental stability issues, she should be the last person leading anybody.