Fenders often connect to the brakes. So, they may go on before the brakes, depending on the actual method of connection.

How is the rack mounted? It might just get in the way, or it might also connect to the brakes, or otherwise be an earlier step. Would it affect how you route the cables? It may also share the lower mount points with the fenders (mount the rack to the inside, and fenders to the outside, I think). So, perhaps mount rack, then fenders.

Bar wrap is the last thing to do, and I often ride the bike a couple of times before wrapping the bars.