I've tried and experimented with a vast number of things over the years as far as plates and washing dishes, which seem to be the two things you're asking about most.
I've strayed away from using enamel or metal plates because they are just too damned hot sometimes to hold in your lap or hand while eating hot meals. I really like the plastic or polypropylene plates that nest together easily and take up no room at all.
For washing, I do have a couple of the collapsible tubs, hoping they would fit in the sink seen in the image below, and they do, but not as perfectly as the cheap white plastic tubs you can get at the grocery or Target. I keep them around though, for when I'm doing laundry on the road or need another tub in addition to the one I use as sink. They nest together nicely.
For washing, my system has evolved to using only one tub. Most of my meals are done with the two pieces you see on the stove below. When done cooking, I put what I want on my plate, move whatever is left into the container it will be stored in as leftover, scraping out the pan as much as possible, then wipe it clean as I can.
Then I put enough water in the pan to heat up on low while I eat. If I haven't used the pan but have other stuff to wash, I put a bit of warm water into a small bowl. Add a bit of biodegradable soap to the pan or the bowl and it becomes the place to soak a sponge and clean the few dishes and utensils I've just used. You can do the same with a Billy Pot, if you use one, which are taller and thinner and may suit you better as a dishwater holder.
I tend NOT to use my kettle for soapy water, but only ever put clean water in it for heating up. My tea and coffee stays a lot better tasting that way.
For biodegradable soap, I like
Dr Bronner's in those tiny 3-4 oz bottles, as it's typically easier to find at co-ops or health food joints when in town than it is to find other biodegradable dish soap. You only need a drop or two, so it lasts a long time. It can also be used for personal washing and clothes, which also saves on stuff you have to buy or store. The peppermint Dr Bronners is really quite refreshing in a shower. Dr Bronner's Lavender is nice for clothes without being overly perfume-y and can be used for dishes and personal washing as well.
Trust me, you'll have people going "That you that smells fresh like spring? Man, that's nice." Using Dr Bronner's around camp also brings back a flood of memories going way back to the late 60's, when I first started using it.
Just washed items get stacked next to the sink until I'm done washing everything, including the pan I've just used for soapy dishwater. I don't rinse one by one as they're cleaned with a full tub of rinse water or under a running faucet, but stack everything until I'm ready to rinse all of it. I save a lot of water that way. Then I rinse it all quickly and easily under a very light stream of water, which gathers in the tub below. It ends up being a good clean rinse, so I leave that water in the tub for later rinsing of other items I might use throughout the day like my coffee thermos, the occasional knife or fork, or small cutting board.
As I most often solo-camp, this has ended up being the most efficient, cleanest, and least wasteful process I've used. I used the same system for a large Thanksgiving dinner in camp too though, for three, with only minor adjustments so know it can easily be scaled up when needed.