Hi there! First of all, I just want to say thank you so, so much for your support and praise! I'm incredibly happy and flattered you're enjoying this rewrite!
I 100% agree with the whole Belphie thing; in all honesty I think the entire situation was very badly handled and then immediately brushed off. It was actually one of the major reasons I wanted to rewrite the plot alongside how everything gets rushed and boring afterwards.
Don't worry about the screentime; Barbatos and the other side characters will appear much sooner than in the original game and will be romanceable from the get-go. If you'd like to, you'll have the option to spend time with them since it's definitely understandable how the brothers aren't the best in the beginning :)
The personality in this new version will be much more detailed and organic than the og, but you'll still be able to be fiesty/hotheaded! This won't bar you from any friendships or anything; rather, it will simply change how the other characters view you and how much they like you, so it might increase or decrease the effort required to get close with certain characters.
Once again thank you so much for your support! <3