You're not really offering significant benefits to the hackers. We're talking about a few thousand dollars cash value. Salaries in silicon valley for sharp engineers are easily six figures. And someone who is relocating to join a startup with no funding or traction is definitely "doing it for the love/risk". I mean, if you can get someone to take those terms, awesome, you rock. But most of your applicants are going to be people who can't get jobs elsewhere, or who just want vacations in Hawaii (what incentive do they have to work hard when they get there?) -- so buyer beware.

I would focus on getting one engineer who is committed for the long term, and that you are 100% comfortable with -- someone that you could share good times and bad times with, for the next 3-5 years. I'd give this person a founder's stake with 4 year vesting (and I'd take impose the same vesting on myself.) I'd wait as long as necessary to find this person, and if I couldn't find them, I'd try to raise enough money to have competent consultants build a MVP at market rates (after vetting said consultants very, very carefully.)

Also FWIW, you are definitely breaking US law if you don't pay them minimum wage and possibly overtime, and the penalties for this are severe (personal liability of directors, treble damages, all kinds of nasty.) You will be in a precarious position if they sue you, because there will be a clear paper trail from your intellectual property assignments.