Yup, garden style bone meal. I got a small box of it from the hardware store which is now kept on hand for any emergency bunny feedings. It's dry and stores on a shelf nicely. The recipe calls for bone meal instead of blood meal, but is there much difference between the two? I'm guessing it's calcium in the bone meal? Or maybe better flavor?
The corn syrup can be replaced by pretty much any sweetener, I'd expect. Although I'm not sure about honey since that usually has a warning on it not to feed it to infants, although I'm not quite sure why? I'd also think that a less refined sugar such as molasses or sorghum would be better for them than refined cane sugar and especially High Fructose Corn Syrup. I no longer use corn syrup since even 'plain' corn syrup is High Fructose corn syrup these days.