Hi,

I think this is one where you need to speak to your health care providers. Let them know that you are breastfeeding, and that it's important to you. The laxatives do not pass into the breastmilk, and there is no issue with the light anaesthetic.
It sounds like the prep for colonoscopy makes mothering difficult - there is the frequent and sudden need to drop everything and go to the toilet. If you proceed with it at this point you may need some-one around you to help out. It would be important to keep breastfeeding where possible. Feeding EBM is an option, but if your breasts become full and engorged they will limit the amount of milk they may - it's probably just as easy to feed the baby as to express. Thankfully, you don't need to eat or drink much to make milk just fine. But you may need support for yourself.