I reject the notion of the Android Protagonist. This was debated to death after E3, and it just comes off as people grasping at straws to get out of being married with a kid as part of their character background. Not that being an Android is any more liberating.

Too me its more of how do we turn ordinary person into superhuman or what is the big picture storyline
So its either the basic plot from bladerunner and or wheres my family.
There has to be a hook that gets us from point a-b but it will be incomplete

If our character was an android, he would have to be a copy of a real previously living person, since Codsworth recognizes the Sole Survivor when he returns to Sanctuary Hills. does that help with your "be who you want to be" concerns if you can believe that your pre-war self at least, was real?

Anyway, as has been said, this plot twist would be seen coming a mile away, as evidenced by the fact that it has been discussed to death since (and before) the initial reveal of FO4.

I would still think it was simply side effect of using the PC's facial parameters to influence the child ~rather than not doing so.

*I think it's a reasonable bet that the spouse or child turns out to be the main antagonist, or the antagonist's tool; (think: Frank Horrigan (/ Darth Vader) recycled as the end boss).

Another plot twist that's heavily expected, but one that I think is much more likely to happen.

Perhaps they'll blend both ideas, and an android copy of your son will feature as the right-hand man of the main villain.