So far I've heard no confirmation that there indeed was an engine fire requiring the crew to complete an engine fire drill and emergency return.
The only fire reports are from those on the ground and likely associated with an engine surge recoverable by shutting off the fuel.
One way of looking at this is from the crews standpoint of what displays did they have and considering the Tower call how to react accordingly.
So to me all the comments from those of us not aboard about the level of emergency and expected reactions from the crew are postulations or what ifs.