You will get lots of good info here if you take time and read previous posts from others. I can't offer advice re: chemo experience, but on the other questions I can. In June 08 I was diagnosed with rectal cancer - Stage 1, no chemo, no radiation, but did have the big LAR surgery with temp ileostomy that was reversed 2 1/2 months later. Most people experience frequent, loose bowel movements after reconnection, but I was the opposite and could not go without help from laxatives. Everybody is different so you will have to wait and see how your body adjusts. Get help from your surgeon when it comes to taking any medications, prescription or over the counter. It took about 4 months for me to get back to some sort of normalcy which allowed me to feel comfortable to get out of the house for longer periods of time.
As far as diet, there aren't many restrictions, unlike living with the ileostomy. But again, your system is unique - what works for others may not agree with you. I started out very gently, low calorie intake and small portions, but a variety of all foods. I did stay away from seeds, nuts and other foods that could cause upset -spicy, rich, greasy, fatty. I ate oatmeal, fish, chicken, carrots, green beans, brocolli, you know, all the "healthy" stuff.
By the way, the reversal surgery is not as bad as the first surgery, but still kind of painful, both from the incision and the re-inflating of the colon. Expect the incision to be sore for a good 4 to 6 weeks after. I was kind of deluded thinking it would be a snap. But the trade off of getting rid of the pouch was worth it.
Best of luck to you.