SO OP, you want a bathroom in a tent?
you will have to put in a compost type toilet. It would be great if your tent had those 'extra' punch out sides for space and turn one into a bathroom unit where you can wall off and do your thing.
tents and bathrooms inside don't go hand in hand usually.
best bet is buy an extra pop up toilet/shower tent and place near your tent and buy a sit down porta-potty unit to handle what you need when ya need it.
I hope I got this post correct in my answer on what the op is asking
I know you have something in mind you are seeking, but it is kinda a thing you have to make and put together to get your end result you want.