[dhead]

Well, Transmission Remote GUI does able to delete files and I'm guessing it does using the Api (and not connecting somehow to the webgui) so it might be possible.

If such feature can't be changed, customized or enabled/disabled via settings then it wouldn't be useful as:
Not all the files are copied and processed by CP & SB (only those that downloaded to specific CP folder and SB folder).
Torrents can also be used for sharing peronal files (non private of course) instead of web servers and cloud sharing services so some torrents should be kept alive forever.

So the best implemantation of such feature would be:
* Folders awared, being able to set different settings based on the download torrent folder.
* Being able to set the time period for the torrent to kept alive.
* Being able to choose if the also the files would be deleted with the torrent.
* For CP, SB download folders the setting would probably be: keep alive for X days and delete files when seeding period ends.
* For default download folder the setting would probably be: keep alive for X days and only remove torrent when seeding period ends.
* For upload folder the setting would probably be: keep alive forever.

If one or more of the above can't be implemented then I think such feature shouldn't be added at all, better set this in SB & CP and just have a manual remove torrent button (and remove torrent with files) on HTPC-Manager.