This has already been translated up to 16 chapters by Fallen Angel Scans, they got permission from the artist to translate it too (though it seems like they dropped the series).
Regardless of the story difference, I feel like the art was a lot better in the first manga. I wish they kept the same artist, but it seems like he moved onto a different manga called Jiisama ga Iku.
I saw this coming from a mile away... especially after finding out the senpai was a masochist. I guess his friend is the only reasonable route left, unless a new girl shows up and becomes the princess he's looking for.
Well the sister would be great too but let's be real, incest never happens...