I'm sure this wasn't inintentional from Minoriko's side...

Never heard about the rice cookies one.

and is it only rice cookies, or also includes regular rice?

No, definitely not - rice is a commonly-used filler in commercial dog foods. Must be something they do to rice cookies that makes them bad for dogs.

Could just be the sugar. Dogs have a sweet tooth, but they can't digest it very well.

No Booze for Momoji?

daaawww...

poor momiji.

The road to hell is paved with good intentions

せんべい = Rice crackers
It contains soy source. And, soy source contains highly sodium that hurtes a dog's kidney.