Back to the drawing board! I've already found solutions to all the problems aside from backstory which I could even omit completely and let the viewer come to their own conclusions.
So... sometimes it's fun when things go wrong. I've decided now that this will be a Braniff machine and I get to create my own "colors." I don't think they had anything involving black, did they??? Black on the bottom? Well, I think I'll make mine black on the bottom (out of convenience, for obvious reasons) and..... maybe a tan light brown sort of sand color up top. Or something. I think it would look good and once the wings are painted properly the mix of colors should all work out.

Like this, but new colors.
Windows. I have none for Caravelle but i have plenty of "American" ones. I'll just use those. No one will be the wiser aside from airliner nerds and, well, this entire thing is alternate universe bullshittery anyway so why not?! We can just say it was license built or something.

It'll be a Braniff Brad-whif.