We could've/should've done something similar...with Sand Island for example. In other cities you do not "ask" people to leave you take them to shelters/facilities. you may NOT live on streets or in public parks.
As I've posted before FEMA had/has trailers small,medium and large for 1-2 people or families. They cost just 1000's(at one point FEMA was giving them to cities). Add water, sewage connection and security patrols and you've basically taken care of homeless problem part 1.
Hawaii does not have anything really called affordable. Latest quote of average single dwelling was $800K+. 
P.S. Part B & C is that homeless need VA care, Psych care and job training.
"Free everything without responsibility gives you just more homeless.