Formula field issues + Drop down list question.

Formula field issues + Drop down list question.

Hello, I am developing an app to find the average score among 4 scores the user inputs in a form. However, the field does not appear on the form (even when I check the box), AND it doesn't show up in the view. 

Here is the function I am using: 
(Work_Quality_Score + Work_Habits_Score + Job_Knowledge_Score + Behavior_Score)/4

Also, I have a lookup field to select the employee being evaluated. Is there a way to have it look up First name and Last name? These are two separate fields in another form.

Thanks,
Dan