"Does it make sense to complete it at the same time as completing the DAR, or is one logically after the other?"

Farallon (primarily a zinc miner) set out upon a parallel course (doing things all at once rather than sequentially) and quickly got in production.

So the idea makes sense, but it entails some risk of extra expense if something fails along the way requiring a redo of something else as a result. E.g. if the prefease were to fail, it might cause by delay, the need for the DAR to be resubmitted. (I'm just guessing here for the purposes of stimulating thought - I know nothing of the actual procedure and requirements)

In this case, since we had a good PA, I doubt there would be any problems with the prefeas. So my overall take is that it is a good move.

P.