File>Open definitely needs to display both binary options. We will fix this.
SaveAs for a file loaded as binary looks like it's working correctly. When you choose "Binary" (not Binary SBCS/DBCS), it's very similar to opening a file as Utf-8. It should show very similar options.
SaveAs from Binary to Unicode: Seems like this should turn off the binary property. We will look into this.
Not all conversions are supported. That's why there are different lists. For example, there's no support to convert SBCS/DBCS to other code pages (except for EBCDIC which is a special case).