I responded with the link to the cinnamon roll page as a pointer towards how to incorporate chocolate pieces into your rollppang.

The main tip was about shaping the rollppang so that you can spread and/or sprinkle on your additions before rolling it all up. I wouldn’t get too hung up on rice syrup or anything else. As @MSYtoJFKagain mentions, rice syrup is similar to corn syrup (sweet, AKA HFCS), so, yes, you could use maple syrup or honey instead. If that’s a problem, just supersaturate some sugar in hot water and let it cool down and use that as a substitute sugar syrup. The real point is that it doesn’t matter. Use what you like, use what you have - you can use a fruit jam/jelly/conserve/marmalade (whatever you call it), loosen it with a spoonful of hot water if it’s too thick or stiff to spread thinly. Melt in a little butter too if you want a luxurious taste. Or do it with a chocolate or caramel spread. Or peanut butter. Add some chocolate chips. The contents of your pantry is the limit. Just forget about the corn (or potato) starch!
Spread it all out then roll it all up. Doesn’t have to have a hint of cinnamon. The tip was about style here not substance.