I am not anaemic but still take one iron tablet a day. As my surgeon says pouchers can have low iron levels and its something that will help balance it. There's no harm in precaution.
For weight, I was down to 42 kg post op and now weighing around 57-58 in 9 months, mostly muscle mass. I've tried different diets to bulk up fast. A homemade weight gain shake helps, made from 2 bananas, 1mango, 1cup milk, 2 tsp peanut butter, 1 cup oats and 1 scoop whey. You can add or deduct anything that may not suit you. I eat upto 5-6 tsp peanut butter and 3-4 bananas a day. Also I use more than required olive oil just to get in extra calories. Rest hard boiled eggs and chicken daily for protein. This works when you're following some sort of training , I do weight training 6x a week.
I've been taking pysillium husk now with reduced amounts as my stool is thick enough with all bulking foods in my diet. But it sure does help in ease of motion. Though initial gas pains and urge to go often can come with it but the gut adjusts to it after sometime.