1. One of the Hawaii shows is mixed down to mono. Does this mean multitracks of that show exist in the vaults at this time? I'd guess "yes".
Multitracks of both shows presumably exist, although, if I remember correctly, the mono mix of the 8/25 show as bootlegged is missing Sloop John B.
That's what I thought as well, and what that leads to is asking how these Hawaii shows escaped the Sea Of Tunes releases when the other live shows done in a similar way for "official" releases were found in the vaults.
The folks at SOT didn't bootleg everything that was involved in the so-called "American Band" issue, although I'd wager a good amount of the high-quality stuff booted in recent memory was from that stockpile of copied tapes. I'd say the Hawaii shows would be part of that.
You raise an interesting point that ties in with my question about the one Hawaii show in mono, and the other in stereo: SOT was hastily mixed while being copied from the multitracks, and that also allowed for "stereo" mixes of various albums. I'm guessing the Hawaii show mixed to mono wasn't part of the same supply of tapes, though I could be way off. If anything I'd guess the Michigan '66 and Hawaii '67 would be in the same place as "official" live recordings originally slated for release, so why not have the multis of Hawaii alongside Michigan and the rest? And why include the Heider re-records and not that one Hawaii show anywhere else?