I don't believe that anyone is hiding this child. Let's assume for a moment that there were children of this family already taken away by social services (hypothetical), and let's assume that some family members might be concerned that Evelyn might be taken away for the same reason. The sheer logistics of how many people would have to be complicit in the hiding of a child, during a police investigation , and under the very real threat of their own arrest for being complicit in the hiding of a child, just leads me to believe this isn't a logical theory. That's just my opinion, of course, but I will say that I have been involved in many many cases of missing children where the hiding of a child as been put forth as a theory, and never ONCE have I ever seen that theory born out.
Again, JMO.