I'll answer the help or hurt question.
Another important factor that the wholly free market doesn't adequately address is the shortcomings of human nature. While anyone who has studied economics will agree that the installation of an artificial price floor can have negative effects on the optimized supply/demand curve, it can not be overlooked the fact that people (especially desperate people) make bad decisions.
What this means is a person who is desperate for a job will accept whatever the going rate is. This rate is what is determined by the free market supply/demand of labor curves. The problem is that wages are very sticky and people who have jobs do not typically look for better jobs. What this means is that the worker who has accepted a job at an entry level rate continues to make this wage and is so poor has little to contribute to the economy. By requiring a minimum wage, the employer has incentive to fashion jobs which require a bit more skill and investment. The worker has similar incentive to develop a bit more skill meaning that for the same number of man-hours more is produced.
Also for the same number of man-hours more is earned and since the laborer is still fairly poor nearly all his/her earnings are spent, further stimulating the economy.
We have not observed minimum wages have the effect predicted by detractors on the unemployment rates the way long-term union level wages do.
That said, it is appropriate that any minimum wage reflect the cost of living in that area. In Washington it is a bit weird the difference between Eastern Washington and Western Washington, or more specifically urban versus rural communities, and I can't say how perfect the minimum wage is.