Replace Modric with another top mf and Real still would've won the CL.
Replace Ronaldo and I doubt it.
You're underrating Modric to a huge extent and overrating Ronaldo a bit. Modric isn't just a 'top' midfielder. He's one of, if not the best, players in that position in the world. Players like him never get the credit they deserve because it's harder for people to see the things they do to help the team and to help players like Ronaldo look better.