Your changes don’t seem particularly drastic, but you should talk to your players before starting. Remember, a campaign isn’t the DM’s story to tell — it’s a collaboration with the players. Cutting stuff from the PHB is always a risk, and assumes you have your players’ buy in before you’ve really earned it.

That doesn’t mean you can’t say no to your players, but it’s more fun if you can find a way to say yes. So, in your campaign, let’s say one of your players really wants to play a Dragonborn or an Orcish sorceror… Instead of shooting it down, try “ok, but you’re the only one.” Then make the mystery of that character’s existence a part of the storyline. The PCs are supposed to be interesting and extraordinary — having one be the first (whatever) is a way to do that.