100 square feet is usually recommended for a beginner's vegetable garden. If you can keep on top of it, though, and not get discouraged if a few things begin to get out of hand, then go for it.

It would help if North/South were indicated on your diagram. Taller vegetables, or those on stakes or trellises, should be planted to the north and west to avoid shading shorter vegetables.

Direction and height of the kousa will also determine whether it is so close as to shade your garden. BTW, is it already there, or planned? If planned, skip it ... Kousa dogwood is considered invasive in many areas, replacing our native species with one that does not fulfill the same ecological role.

Seeds, depending on variety and how they have been stored, may well be viable for considerably longer than a couple of years. Some are viable for 5, 7 years, even longer. If in doubt, do a germination test: place about 10 seeds (fewer if you don't have that many to spare) on a damp paper towel in a baggie, close it, and set it aside in a warm, dark place for several days. You will soon have clear visual evidence as to what percentage of those seeds are still viable.

Comfrey *will* spread ... vigorously ... even if you plant it in a pot. I have it in my garden, love the flowers (so do the bees) and regularly pull/dig up the spreading shoots to add to my compost bin, where it adds nitrogen and minerals the long taproot has mined from deep in the soil. Here in my zone 7 garden the plants are just emerging, and already I see shoots coming up 5 feet away from the mother plant.

Yarrow is excellent for pollinators and other beneficial insects and for birds, but it will also spread aggressively by underground runners.

Look into the pros and cons of tilling, especially since you're in a botany club. There is a growing faction that advocates no-till gardening in order to avoid disrupting the soil strata and the organisms/micro-organisms that inhabit those specific strata, creating a healthy, productive soil.

I assume you are young (since you are in university), and therefore have plenty of energy and strength, but there is also the option of preparing the garden as done in lasagne gardening, for example. Layers of cardboard or newspaper are placed directly on the grass, watered down, then layers of compost materials layered on in alternating layers (like making lasagne). I've done it and found it to work beautifully, turning my gray-brown sandy soil into rich, dark, friable loam.

Do you plan to fence the garden? If there is wildlife in the area (deer, groundhogs, rabbits), they will be only too happy to come harvest your crops for you. Exclusion is the best means of protecting your hard work.

Next winter, if you really want to turn your botany club members on their ears, try winter sowing. Check out the forum on this site or visit wintersown.org. It goes against everything you were taught, but it works. My lettuces and kale sown in early February went through multiple freezes after germinating and I now have nice little seedlings ready to plant out in the garden.

I'll also iterate about the time commitment for such a large garden, but also encourage you to go for it if you are willing to try it.

One of the first and easiest ways to start a garden is just to till and start planting. However, once you find that you really get into it and like it, there is quite a lot to learn. One of those things is not to start too big at first. Being that you haven't gardened in a long time or even done it before, prepping that garden area, even without the idea of amendments, nutrition, and mulching, takes a lot of time and effort. That's just to get it started. Then there is a lot that takes place during the growing season.

(Note: Upon re-reading, I see that you might have help from the others in your club or school if this is a public garden)

My first year that I got into gardening, I had about 60 square feet of space and while working on it in the evenings and weekend, it was quite a lot of time.