I only made it through chapters 1-3....
Just kidding!
Yeah this is all bad. I only made it through about 30 seconds of the two of them singing together. That was HORRIBLE. It kinda made me want to cut my own throat. So staying with that plan is no good.
But this was no good to begin begin with. Having two lead singers with very similar voices is not great.
You have a couple of choices here.
1) Keep one of them and hire a completely different voice to join the band. A female couldn't hurt. There's a lot of female fronted radio pop rock from the 90s and a little before and after.
2) Start over vocally speaking.
The problem with either is that people seem to have chosen sides. Even the original three of you won't be completely satisfied with the outcome.
Good luck with this.