Start with small doses of Iodine
and niacin if you need to, and build up the dose gradually within the refeeding period. Niacin can have a strong flushing feeling so depending on your reasons for taking it, would niacinamide be a better alternative?
The other nutrients you have mentioned can be started straight away, but again build up slowly until digestion is fully restored and your appetite strong. Nuts can be hard to digest unless masticated thoroughly so make sure that they are.
Again build up exercise slowly at first, gradually increasing the amount and intensity. Listen to your bodily needs and as determined by your body. Does anyone tell you when you need sleep? or rest, or food when genuinely hungry.
Listening to the wants and needs of your body is your greatest asset, you just to have to tune in and listen very carefully.