One of the things that is clear as mud is the plumbing and wiring of a micro-home. None of the micro home websites cover how to figure out what you need, and how to do it. They just assume you will hire someone.
Plumbing. The Micro home, if it is to be mobile, needs to carry everything inside the structure. This means tanks for fresh drinking water, Sewage from the toilet, and "grey water" from the shower and sink. you really need them in places where they are protected, and you need to keep them from freezing by insulating them and even adding heating to the tanks. You also need to know how much each tank contains so you are not surprised one night with a toilet that will not flush as the sewage is completely full. Luckily the RV industry has been doing this for decades, so it's not a hard thing to deal with, but it takes some planning. Your sewage, or Black water tank MUST be under the toilet, in fact the toilet mounts to it. so this means that structure design under the bathroom must be set up for accommodating the black water tank.
How big of a tank will you need? that depends. If two people are living there full time, you will need a large one to avoid having to empty it often. pulling up roots on your micro-home to find a sewage dump station is not something you will want to do weekly. If you are clever and make sure you do all your personal evacuation when you are not at home, you can get away with a smaller unit to cover those days you just cant wait or the middle of the night bathroom run. In this case you may be able to get away with a portable toilet or a composting toilet, skipping the sewage tank completely. This has the huge advantage of being able to take your waste away in a car or other vehicle instead of moving the whole home.
Fresh water can be as simple as a water jar and faucet above a large bowl like they did in the 1800's or a fresh water tank with pump and built in sink. If you want a nice shower, you will want the water tank, water heater, and pump setup. Most of the time the water tank is under a built in bench seat or cabinet. the pump sits next to it and flexible PEX piping is used. Again, INSULATE everything and even run electric heater lines for the tank and pipes.
Grey water you have more options. RV's use a tank to capture all of it, but if you use only sink water and shower water, you can use it for irrigation of plants. If you are near a water source, dont just let it run on the ground as it can contaminate a stream or other water source, re-use for garden irrigation is perfectly fine. I personally will let it just seep into the ground if I live in a spot away from a stream or other source. a Soaker hose will spread it out to water a larger area. If you are building a mobile micro home, put in the tank as you will never know what rules you need to follow.
Hot water is another thing to think about. RV water heaters come in Propane and propane/electric versions. they are small but must be mounted where they vent outside. They have very little insulation so cold climate damage from freezing is a possibility. if you build your home right with a "utility box" on one end that you can control venting and creates an air space, you could insulate the area when the hot water heater is not in use to prevent freezing. but don't block it's venting. that can become highly dangerous.
Plumbing is incredibly simple, you will have 1 sink and 1 shower/ toilet. if you manage layout right the shower faucet will be on the same wall as the sink or close to it. this will make runs very short and very cheap.
Lastly, figure out your average water use for a day. and consider how often are you willing to go get more water if you are not where you have hook ups. If you use a very low flow shower head and and do things right, your shower will only take 5 gallons of water. that means you have 10 days of showers with that 50 gallon water tank before you need more water. RV supply stores have wheeled 10 gallon water tanks that you can buy so that you can cart home your own water from another source easily in the back of a car. Or better yet, join a gym. and every morning on your way to work, go to the gym, work out for 10 minutes, and then shower and get ready for your day. now you don't need to replace your water as much. Side effect is that you become more healthy as you are now working out daily.
Remember this lifestyle change is a big one. You need to make changes inside and outside the home. Taking advantage of other resources like a Gym membership, work facilities, etc to reduce consumption at home makes a big difference in not only your efforts in day to day living, but your costs as well. a $35.00 a month Gym membership is cheap if you don't have to pay a water bill and the propane used to heat that water.
Again, this matters if you built mobile and will be nomadic. if you built on a permanent lot, these issues are not something you will have to live with.