For a Dev who's only been doing this for a year, this is some fine achievement.
Christmas Eve was extremely polished for a first game: this promises even more. I love the richness of the characters. I love how consistent they are, though we do see glimpses of them evolving.
Keep going as you are, Jonesy!
I've just finished editing the script.rpy file and played to the end of chapter 1. My changes are mainly to reflect the fact that I'm British and I use 'Mum', rather than 'Mom': 'street', as opposed to 'sidewalk'. Things like that only niggle me when I think of myself as the MC and suddenly I'm using words I never would in real life. I saw no need to alter anything major.
I did alter age references in the dialogue, because in my eyes, Eve doesn't look 20. Other than the opening section, there's no other specific reference to age.
To be honest, if you object to little things like this, it's no big thing to customize your own game. Yes, it takes a couple of hours, but it gives you an idea as to the work that goes into the game... a fraction of the work.
As far as the 'step-cest' debate goes, well, there's nothing wrong with debating it, but we'll all end up in different camps. As someone else said, the laws about this vary from country to country. Not only that, but cultural beliefs vary widely, too. Personally, I think that the story and how well, sensitively, credibly and thoughtfully it's written is way more important: and the writing here is good, very good. I only really object when dialogue has a stepdaughter saying rubbish like, "Do you want coffee, Stepdad?". I mean, who says that? It's then obvious that they are biologically related but the dialogue is just... surreal. There's none of that nonsense here.
I would prefer no step relations, but as others have said, that was in this saga from 'Christmas Eve'. Having said that...
... there's nothing to say that the step relationship is actually true. It could be that Evie and Daye actually believe that the MC is their stepdad, but he's actually their biological father. I can think of scenarios to fit that bill. For now, I'm perfectly content to see how Jonesy progresses this: it's Jonesy's game after all!
Oh, and to Jonesy...
... don't fret about deadlines. You're giving big updates in a pretty short space of time. Anyone who cares about your work won't grumble. Anyone else doesn't matter. When I needed to correct flaws (that I agreed with) in my Skyrim mod, I was desperate to get the updates out! I felt like I was letting every new player down with every minute I spent re-writing 'Papyrus' script, altering graphics, effects and dialogue, but, but... rushing it would have led to more problems. Take your time. I, for one, will appreciate it.