In theory you are not being unreasonable OP but as others have pointed out, a list of rules will not be well-received. The best you can do is make arrangements ahead of time to protect some space and autonomy for yourself.
Five weeks sounds like an absolute nightmare; I would go mad!
Let them use the low-level shower. Can you add a hand-held spray attachment or something so that it's more convenient to get at various parts of the body? Or they can bathe. Or can the spray be augmented/repaired before they come? It would be worth the money.
Make sure there is a lock/hook inside your bedroom door so you can retreat there for a nap with the baby when you feel overwhelmed. Fall back on "doctor's orders" as needed if they protest.
Make it clear from Day One that breakfasts are "on one's own"
Do not feel obliged to take them to the yoga or swimming classes. Those are your retreats.
Enlist friends or family to come over at certain times to provide a "buffer" if tension is building, or to meet you out so you can vent.
Don't worry about thing like rearranging kitchen etc. - very annoying, yes, but will keep MIL occupied and your DH can put it back when they leave. Take photos now of how you want it returned to order.
The bathing the baby and nighttime routines will sort themselves out. I understand your protective feelings but babies have done fine in multi-generation homes for millenia. Pick your battles.
I would be going to the GP and asking for diazepam, seriously (can you take it while breastfeeding?) in case you are driven to the edge by the close quarters. I wouldn't want my own parents to be under foot for five weeks let alone near-strangers whose language I do not understand. Good luck! 