PC adjustment

ok so one of my players created a PC and had boxes checked that shouldn't have been and some unchecked that needed to be check marked.  if we uncheck Optional Class Features and Customize Your Origin and then also add a check to multiclass requirements will it force him to choose new options or since his character is made will it remain unchanged even by adjusting the boxes in character home tab?

No, it will restrict further selections though.  

ok thanks a bunch thats helpful to know. i am very new to this