I think the 9000 would work well. It has all the capabilities that you listed, plus many more that would be useful in composing. You can hook a computer keyboard into it for direct data entry and fast navigation. Hard drives are quite inexpensive. Video out might be helpful too.
There are four line outputs, plus easy pc connection. If the styles you need aren't there, there are literally thousands of free ones available, and the 9000 will play them directly from disk.
I'm sure there are other suitable arrangers, but of my recent experience with the Solton and Technics, the 9000 stands out for this type application, in my opinion.
Hope this helps.
DonM