Image: UbisoftOfficial screenshot from Ubisoft.
Liberty unlocks when you capture all 21 FND bases in solo play. It is one of the longer trophies, but each base you take becomes a fast travel point.
1. Check the map for every FND base. 2. Capture each one in solo play. 3. The trophy pops when the last base falls.
Take one quietly to get Ninjerilla on the way. Use a Security Control Center where there is one for Didn't See That Coming!. If you still need Co-Dependent, do that one in co-op first.