Hi,
I have had a J Pouch for almost 30 years and can eat just about anything I want. Diet is all trial and error with the individual and there is no approved one consensus diet for all. One phenomenon I have seen on this board is the emphasis on short term digestability rather than long term health of the Pouch. At your early embryonic stage of Pouch development, clearly, short term digestability is really all that matters. After 30 days or so, you may begin gradually adding new foods, one at a time. What doesn't digest well then, however, might not be any problem in a year. You have to be prepared to apply trial and error experiments at the 1 month, 6 month and 1 year marks. After one year you will probably know what you can digest well short term.
What is good for a J Pouch long term is the subject of much debate and discussion but a consensus exists that limiting sugar and carbs is helpful in not breeding bacterial overgrowth and the conditions that it can lead to. This doesn't mean, however, that you cannot eat sugar and carbs or that you must necessarily reduce them, as some people have no problems whatsoever eating the same after surgery as before, or in eating anything that they want. I believe you should experiment with foods, but how you feel should dictate the aggressiveness with which you do so.
Good luck and best wishes for a full and speedy recovery.