We install or help people install newer kernels regularly. It's rarely an
issue. Even where an issue does exist you can select to boot an older kernel.
Here are the directions for installing a newer linux-libre kernel in Trisquel
and other Debian/Ubuntu derived distributions:
http://jxself.org/linux-libre/
Now I wouldn't recommend installing packages from Debian/Ubuntu under normal
circumstances as you might risk breaking the system and there are ethical
issues. If it is something that isn't packaged for Debian/Ubuntu then it
might be OK to install.
If I understood you right the main problem is a lack of funds. Which project
you contribute to matters less than that you are contributing.
Join the free software foundation, make a contribution to the lightspark
project, or the free version of the distribution you use.
There are also other projects like OpenShot and similar which could use
funding. The developer isn't even making minimum wage.
