yes, it is a carrot that is cut with a flower shaped vegetable cutter. this is the one i have here: [link]
Yes you can use any meat you like. Pork and Chicken are the traditional meats used for making katsudon/chickendon
when you make this please make sure to pay very close attention to the directions. I made this sort of odd in explaining certain parts. in the ingredients it says 2 cups dashi-stock.... your actually going to make it using hon-dash + 2 cups water so just ignore that part. put soy sauce last and only add to taste because its very salty and if you add to much there is no fixing it. it is to be eaten that day and possibly the next day but no later then that. enjoy!
i would not suggest it. rice if left in the fridge for more then a day becomes extreamly dry and then it is no good. the pork should be fine provided you put it in the fridge along with some paper towels to keep it from becoming soggy with its own oils. the sauce however will only last a day or two in the fridge. i have never tried freezing these items before but it should be ok. its refridgeration that has problems. its best eaten immediately.
actually if you freeze rice while its still pipping hot, tightly wrapped in a heavy duty saran wrap it stays pretty fresh and moist for quite sometime! almost like you just cooked it. This looks really yummy! I had it before but never knew how to make it thanks aton!!