If the Intel graphical chipset is used, then it is perfect!
Linux-libre has free drivers for both nVidia and AMD cards. The problem with AMD cards is the absence of free firmware (code that is running on the GPU, not the CPU).
Extensions are for GNOME Shell. Not for Trisquel's default desktop. If you want to try GNOME Shell and have the ability to use extensions to it, then install the "gnome-shell" package (e.g., from the "Synaptic package manager" in "System settings"), log out the graphical session and log in again after choosing the GNOME (rather than Trisquel) session. On the login screen, it is an icon to click near your user name.
I think you can swap the Intel Wifi card with the one you found at ThinkPenguin. Samsung is not known to use a DRM that prevents you from doing that.
