Changing cell values based on other cells values

Hello everyone,

I am attaching an excel file, I'm trying to figure out how to change the values of other cells based on the input of the previous ones.

In the example attached, I managed to conditionally format and change the cell values in E5 based on the input of the previous cell if it is >= 60 it will change to green and the letter will change to C (Completed) If it is <=59 it will turn to Red and the letter will change to "F"

What I need is to change the letters in cells G5 and I5 to "S" if the value in E5 is "C" and so on for the whole row, here I just included 3 stages but the stages could be more in the row.

Thank you.