I just noticed this, not sure if it should be in the DIY section, or elsewhere (because DIY section is for write-ups on how to do DIY)
I would think that the answer is the gas (definitely don't undo aircon pipes with gas still in the system), and the front bumper.
Once the front bumper is removed, the rest should be obvious. There is a bit more complication on the aircon in the diesel than in the petrol, but otherwise similarly straightforward (I replaced the condenser myself in my petrol Accord)
It was wether out not the bumper had to come off that I want sure about really. Gas has already been removed after confirmation it was leaking. I might have a look at this this weekend now.