Question 1: "know of" and "know about" are somewhat interchangeable. In very general terms "know about" tends to be used in situations where specific information is either being sought or provided, while "know of" is used where more general, non-specific information is in question. See the examples but keep in mind that the distinction is not hard and fast.
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RayHSee the examples but keep in mind that the distinction is not hard and fast.Did you use hard and fast as an adjective?