Not if you install another launcher (e.g OpenLauncher, Lawnchair, Omega) before you uninstall Bliss. See this post for details of how to uninstall Bliss (or any other system app)
Trebuchet is already present in /e/OS (as a system app), but cannot be started in the UI. But you can try uninstalling trebuchet as described in that post (its id is com.android.launcher3), then install it as a user app.