As far as I know we have two ContentSync configurations within any AEM Mobile project:
There is no problem with extending of Shared Resources config, though extending of Article config by default does not make any sense since the links in the built HTML code will be relative to HTMLResources folder, e.g.:
<img src="../HTMLResources/content/dam/demo/slick-1.png"> (custom image handler)
<link rel="stylesheet" href="../HTMLResources/etc/designs/epm-aem-mob/clientlibs/article.css" type="text/css"> (clientlib handler)
Would like to clarify, is there any solution or workaround which could allow set custom relative paths for specific used within HTML page?
Any suggestions would be appreciated.