I’m just finished this guide/procedure for the very first time. I didn’t remove the heat sink (step 55 to 57) with a lot of patience and with extreme caution, I remove the logic board with the heat sink attached on a single part, very carefully with the fan and the I/O board, so, it’s possible but not recommend, before this steps remove the MagSafe board first, the full procedure took 3 hours.
thank for this amazing guide!