1). You want just that thread, filter: -* +*t=56686* 

where to put this filter? 

set option> scan rules> +*.png +*.gif +*.jpg +*.css +*.js
-ad.doubleclick.net/* -mime:application/foobar

-* +*t=56686* ?
2). You want to reject everything in that thread but not the non-print
verion: -* +*56686* -*showthread* 

where to put this?
3). You want the thumbnail images (from all sites) so allow them also:
+mime:image/* <<---- put this in MIME types> associations>  
file types? MIME identity? 

4). The links all have Don't Follow, so you  must disable robots.txt rules: 
options -> spider -> spider no robots. txt rules? 

%). The attachements links are in the form:
How to get it? 

You'll get the attached images since you already allowed them. If you want
the
attached templates and zip files: +*.zip +*.tpl ? like this? +*.png +*.gif
+*.jpg +*.css +*.js -ad.doubleclick.net/* -mime:application/foobar

+*.zip +*.tpl?
5). The links are not localized....
Always set options -> build -> no external pages so anything you don't get
will be obvious. <<---- this one i understand.