1) If someone wants to do the work for $1/hr, and isn't coerced or under duress to accept the wage, then it's fine. A wage should be an agreement over the value of said work. The value is a compromise between the value of the employees work from both the employer's and employee's perspectives.
This breaks down in the cases where the employer is withholding the value of the work to the company, or where there is widespread wage oppression. Both are wrong because they prevent the employee from effectively bargaining a fair wage.

2) You are not wrong, assuming the wage contracts were clear.
I think it's morally reprehensible for one person in a company to earn a lifetime's worth of money while other people in the company are living from hand to mouth. I don't know the "right" ratio of profit distribution, but when one person's net profits translate to long-term economic stability, then I think the lowest full-time employee should not be in constant crisis over short-term economic issues (I.e. feeding, clothing, and sheltering their family).

3) See 1). If the bussboy knows the actual value his position brings to the company, and is empowered to discuss the matter of his wage openly with you, without fear of losing his position for having the discussion, then it's fair. If that particular employee does not think it's fair and is somehow coerced to keep the job at a wage he resents, then that's a problem. Assuming the bussboy is free to quit, and even to report about / protest the issue publicly, then it's your problem if bussboys keep quitting.

4) Determine what the actual value of your work is to the company. Subtract the amount that you are personally willing to invest in the company's future. That's fair pay.
Sure the company wouldn't exist if you didn't start it, but it also wouldn't exist if any task that needed to be performed had failed. R&D, Accounting, Logistics, Manufacturing, Marketing, etc... all these roles play a part to the profit of the company. Determine the appropriate sourcing of company profit and distribute the profit accordingly.

5) No. Humans make value by creating things that save other humans time. That value is inherently subjective and self-oriented. A person, or team of people's thoughts and effort created a value that wouldn't exist otherwise. They should be entitled to the benefits of their effort. The greater the benefit is, to the greater number of people, the greater the reward of the initial effort of the creator(s). It is unfair to expect a person or group of people to make great sacrifices for an end that does not yield them great reward.

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All of this is fuzzy. I've left it vague on purpose. It's all relative in ethics.... Call me a relativist... there's worse things for a physicist to be called.

To me, it's functioning free-market capitalism when it looks like socialism, but the government isn't involved.