Can both manual item definitions and items for things be defined for a 2.0.0 binding?

I am migrating from OH1 to OH2 and have an Onkyo AV receiver that is recognised by the Onkyo 2.0.0 binding. The paper UI presented several things for zones 1 and 2 but the list of things isn’t a complete list of all the functions I was using in OH1. For example, there are no things for zone 3 and also no thing for the listening mode (stereo, dolby surround, etc) for zone 1.

My question is, can I create items for the missing functions in the old way (in an onkyo.items file) as well as use items created via things from the 2.0.0 binding? Or must I revert to the 1.9.0 Onkyo binding and copy over my items file from my OH1 server?