For those of you who have never dug and used outhouses, dig 2 holes smaller one for urine and big one for the number 2 mixing the two leads to horrific smells. We use an auger put in a drainage pipe to 8 feet (gravel here) this is also.where your hand wash water goes. If you have kids make a smaller hole for them freaks them out having to use fullsized hole some kind of fear of falling in or monster living down there at night lol. Have a shavings bucket there so everyone sprinkles after a number two.. use a small yoghurt container or people.tend to use a whole bucket of shavings on one outing.
Sink can be a bucket with drain on bottom we have a 80 gallon tank on roof which we fill weekly there is a hose to a faucet one temp only lol. There is towel for drying and a liquid soap dispenser.
You can make a big enough outhouse for 3 holes more than one hole helps vent it keeping smells down but good use of wood shavings and lime and it smells better than many public toilets.
In spring to fall we ask the guys to pee on the hay piles that where cleaned from the poultry coops it helps the breakdown and does not smell. In fall we turn and cover piles by spring they are soil amenders.
Side note get a small bucket with easy to remove lid place the toilet paper and set wipes in there or squirrels will use it all up to make nesting material damn limb rats.