If you allow illegals/homeless (or anybody) to establish residency on any of your property, you will NEVER get rid of them. All they need is a piece of mail or a bill naming them at the address, and they can and will claim 'squatters rights'. Then, you will have to go to court to evict them. In the far-Left Liberal court system in America today, the eviction will more than likely be denied unless you can provide an alternate place for them to live. Over time, according to American Law, they can claim ownership of the property you so compassionately allowed them to occupy.
In short, once you 'help' someone by allowing them to stay on your property, you become responsible for them for life. You will open yourself up to a world of trouble and expense all for nothing.