Cinnamon from T8.0 onT7.0?
Cinnamon is packaged in Trisquel 8.0. Can I install it on Trisquel 7.0 from the 8.0 archives?
Although I can't speak from experience, CalmStorm's probably right. The problem is that, unless Cinnamon is very unusual in this regard, it's going to need reasonably recent dependencies (or whatever those were back when it was packaged). Those dependencies will be the same, and eventually it'll end up trying to pull in half the operating system- which is going to cause turmoil.
That doesn't mean you can't package Cinnamon for Belenos- it just means the version you package needs to come from around 2014 or so. The exact date will depend on what versions of its dependencies are currently offered, but- if Ubuntu is like Debian, which I'm pretty sure it is- these won't have shifted much from initial release.