They're avoiding surgery until you're well. The diarrhea isn't the problem; it's the symptom of an infection. They're waiting until you're healthy in order to give you the highest chance of survival and the lowest chance of post-surgical infection.
You should wait at least a month to dye your hair after surgery.
You should wait until you are off any medication relating to the surgery, and the wound from the surgery is visibly healed.
I'd wait about 4-6 weeks maybe
later
one month
3-5 years
after surgery? well you should wait a few days or weeks until you get back to your normal routine before you had the surgery
after two months from surgery
I am using my computer after around 96 hours of my cataract surgery; and it's fine.
Until the pool is open for business
Why would you need contacts after the surgery? You need to ask your doctor about this one.
When all wounds that can be exposed to those chemicals are healed. Your doctor can give advice when that will be.