Totally absurd for camping/backpacking use instant coffee. There's nothing wrong with decent instant coffee i.e. Gold Blend (if you can afford it!!). Ground coffee is nothing but snobbery the only reason I use it sometimes (at home!!) is because decent-ish ground coffee (bought online) is cheaper than decent instant coffee. Ground coffee is also a lot of faff and having to clean the damn thing out.
I eat cheese as trail food, small pack size and very high in calories for it's weight, you can eat it as it is on it's own and add it to a meal (pasta etc) when you're cooking. All those oats / oat bars are good for is giving you the shits. Expensive all this oat bars rubbish is too for what it is. You may as well eat chocolate. You probably only buy oat bars in the first place because you think you're posh. You're the sort that buys bottled water, you know who you are.