I'm done. Christopher Steel II and his three pre-existing clones overtook all of Sunset Valley, buying over and fully upgrading everything, cloning themselves at the science facility and evicting everyone (including the Landgraabs, Altos and Christopher Steel I). The job was completed Week 3, Day 4.
Final Score: 18 days.
This was actually quite demanding despite the short length (game-time, at least). Those 18 days game-time really took quite long. I kind of know where I went wrong in the end.
Anyway, now I can install Showtime and it's off to the puzzles of the Trophy Room (which I have no idea how to tackle), after I explore around a bit!