Actually you should be working in that way. The only problem I see is that you need a plist file (which Aseprite cannot generate at the moment). I have future plans to create a template system to add different output formats (.json, .xml, .plist, etc.).
Maybe I can help you in this .json to .plist converter (which them will be useful to create a template for the new “template system”). Do you have a simple .ase example with for example one character, two animations (two tags), two layers, and how would you like to see the .plist output (and if it’s possible, it would be nice to see the expected .plist as a text/xml file).