Once you reach Chapter 6 in the main story, Swift Solutions will have some new citizens available to recruit. All you need to do is pay the required number of Tokens of Gratitude (listed above), then find the citizen in their respective place to finish the quest. Proteus can be found in the watery area to the south of Hautes Harbor (you can go up the stairs from the docks at the beginning near your ship, then drop off into this area now).