I never heard of Hugelkultur, I be honest, I don't go for latest fads, buzz words and so on but good luck to you if you're trying to grow something, anything at all yourself.
What I do know is if you put, dig, stir (whatever you're able) all the veg waste, muck etc you can get, the soil will get better. For those of us that remember "the answer lies in the soil". If the soil gets better, your plants will grow well - Also the weeds......
Dig your weeds in. If you have long or strong rooted weeds, like dandelions, nettles, well anything that it's an effort to get up, KILL them before digging in. I do this by leaving them out on a path or any place where they won't re-root. Bucket of water, pile with a black tarpaulin or cardboard on top, or a fire, just don't make work for yourself by allowing them to re-grow. Lightly rooted weeds can be left in a heap or dug straight in. just make sure there's about 6 inches 15cm of soil on top.
Horse muck is good, but nowadays I only get about 3 good sacks of fresh stuff and it's left 100 metres away from the house because of getting bites from horseflies - nasty for me.
You have to leave fresh horsemuck out to rot well, so there's no avoiding the associated problems if you have a small garden, same goes for all fresh muck.
Amaranth - wouldn't bother unless you have a large area, say 100 sq ft - you won't get much out of them unless you can do it in bulk, dry it and store it somewhere
Tomatillos - well, they grow well, and I grew them for about 10 years, commercially making pickles and selling plants on the side. I wouldn't bother doing many of them if I was you. To my mind, the taste is not that exciting, they don't taste as good as tomatoes, they tend to have more pips. They grow like wildfire, so they're easy. I grew the purple and the green, no real difference. Physallis edulis is a better bet, sweet orange berries in a papery husk - everyone likes them - I haven't done them for 5 years or so, this has reminded me to sow them indoors in late Jan/early Feb.
I never grow sunflowers except for the flowers, but I think there are some that are better for seeds, maybe people here will know. Courgettes are good, I like to grow yellow as well as green ones, and have them really tiny, raw with salads, as well as cooked.
Grow what you DO eat. Especially grow the things that are dear in the shops - raspberries, asparagus, baby potatoes, strawberries, herbs, baby leaf salads - only you will know what you spend too much on in the supermarket.
Best of luck, Jenny