Midway wasn't keeping Japan contained in the South Pacific - the two were as militarily separated as Midway and the Aleutians. Japan probably could have taken the South Pacific in early 1942, in fact - but instead divided her fleet carriers up piecemeal, available to be defeated in detail.
As it was, with help in the Solomons, Midway turned the war in the Pacific. Least that's how I understand it, though I've certainly read more of the war in Europe. :)
Japan invading Hawaii would have caused a famine if they succeeded - it'd be even harder to keep supplied than Midway, but with dozens of times the population.
In my opinion Midway marked the turning point of the war in the Pacific, but that turning point was inevitable as long as the US could credibly say "we're going to commission 6 fleet carriers with a full suite of aircraft over a 12 month period". There's a great video here [0] that illustrates the differences in production over the course of the war. For instance, the US commissioned 17 fleet carriers and 9 light carriers from 1941 on - Japan commissioned 7 and 1, respectively.
Had they got to Hawaii, I imagine the experience would have been similar to all Japanese occupied territories -- famine, brutality, extensive forced labour and systemic murder. So long as the troops are fed, and enough comfort women can be found, nothing much else mattered...