Down is far warmer weight for weight, and it doesn't need to be 800fp unless you're obsessed with lightweight kit, or just obsessed with kit, and have money to burn. 700fp is good stuff, but even the 550fp used in the more budget kit will do a good job.
The Aeropress isn't a wonder machine, but it does make consistently good coffee with a minimum of faff. I particularly like the fact it's very easy to keep clean, so you don't get the bitter taste of previous brews.
But for backpacking I stick with coffee bags, which produce a very decent brew with no messing about.
It's definitely worth paying to go to a podiatrist like Rebound. Only you can know the value you place on your physical and mental wellbeing, but for me even a much higher cost would be well worth it. But I would try the NHS first, because it does offer a very good podiatry service in some areas and at some times — it's one of those postcode lottery things.