Can the 100% owner of an LLC have Schedule C income?? or since it is a corporation, must he have W-2 income???

Watch this non-answer!!! It all depends upon your state income tax and business governance rules. Although I have only seen K-1 income generated from Calif LLPs and LLCs. I would guess that you could have W-2 income. I don't know of anyway that you would routinely have Sch C income for the LLC's business. But, check your state's rules

An LLC with more than one member can choose to be taxed as a partnership or as a corporation. If it chooses to be taxed as a corporation, it's workers, including the owners, are employees and receive W-2 forms. If it chooses to be taxed as a partnership, the owners are not employees for federal tax purposes and instead receive a K-1.