I agree with your partner. We actually don’t have anything against the ingredients in this culinary gang bang, but the manner of their fusion in this roll is… unbecoming and deeply unflattering to all. Cooked well, handled thoughtfully, they could make a sincere and tasty onigirazu - but the reduced shelf life would discount this option as a festive “on the go” supermarket offering. Could be worth trying on Boxing day (12/26) with some salted rice and nori, but perhaps not with vinegared sushi rice.
I’m looking to make Brussel Sprout kimchi this year, we’ve already fallen hard fir cauliflower jangajji

Mochi is my perdition, and the sheer variety of foods that use pounded mochi rice or mochiko is staggering, not just in Japan. But, yes… mooncake,

Closest I know of in Japan is Kuri Manju which is baked rather than steamed. This is what I had originally had in mind for my quince and mincemeat before I went the Taiwanese inspired pineapple cake route. Funnily enough, as we ate the last of the quince mince cakes (each is tiny, about the circumference of your thumb and first finger) MrLapLap said they reminded him of manju and he thought they’d do well in Japan. And, again, you nailed it; shortbread does indeed describe this kind of pastry but it’s different enough to meld with the quince mince rather than just offer a case to entomb it as a pit of over seasoned sludge.
I got a request for another batch, so my mission definitely succeeded.