I know someone who was stuck in Barbados until he could document when and how his crew left. Not valid in some states, doesn't protect against negligence, starts relationship on awkward note. Carry good liability insurance, and make sure it covers crew. Assume good will and hope nothing happens. No money changes hand on per-day basis.
Crew pays their fair share of provisioning and fuel costs.
Yes there are legal implications if money changes hands. If you pay them they are crew, but as we have stated before, even if money does not change hands, when you enter a foreign port they are still crew. I suggest a fee per day, you manage the money. This may start to look like a charter which means you should be licensed. But in actuality this problem would be rare.