If you truly are building a company all of these methods can have pros and cons to them. Hiring a consultant is more like hiring a business or a sole proprietor to help you. They probably have other clients and you only be able to hire them on a project basis and you have no control over how and when they work which is also very similar to an independent contractor. Both of these types of contracts strictly imply that you have no control over how they run their business and in fact can have many other clients and work for you when their schedule allows. On the plus side of that, you are not obligated to provide training, resources such as lap top or office space or even payroll taxes and workers compensation insurance since they are independent.
The big question is how do you want to control these people and what do you want the relationship to look like?
Do you want them working exclusively on your projects and not have any distractions of their businesses to compete with your visions then you should hire then as employees. Now you will have to provide work comp insurance and also pay payroll taxes when they get paid both to your state and federal government but if you plan on having the most control over their work, times of arrival and departure to work then this is the best and most recommended way. In fact, you CAN hire employees on a commission only basis if its paying a continuous salary that you are worried about.
Note: if you hire them as independent contractor make sure you have an independent contractor agreement in place signed by you and the I.C.
for the definition of independent contractor vs. employee this should shed a ton of light for you.