Solved my own issue this time.

Here is the formula that worked for all rows:
=INDEX(A2:F2,COUNTA(A2:F2))&","&INDEX(A2:F2,COUNTA(A2:F2))&","&A2&","""&B2&"/"&C2&CHOOSE(COUNTA(C2:F2),"""", "/"&D2&"""","/"&D2&"/"&E2&"""","/"&D2&"/"&E2&"/"&F2&"""")

Thanks to everyone who tried to help!