I think it's best to use custom code to handle seeking, just like Gizmo.
There's no reason JRemote couldn't do that, and I would think WebGizmo could as well using Javascript (paging javascript wizards).
I don't disagree at all.
Should work. Nothing in the documentation says the segments are size-limited (in fact, it says the opposite, just that they should be "equal"). I think I found some stuff on Stack Exchange earlier (maybe even those threads I linked before) where people said they could serve the TS as one big segment, they were complaining about needing to serve it via HTTP. But that's not your problem.
And, you're right, you could handle WebGizmo through JavaScript, since your "server is smart" and knows how to generate the TS file at the right point as it goes. In fact, JRemote could just use the MU38 to "get it going" and ignore it for all seeks, and just restart via MCWS. That might work more reliably, and you wouldn't have to worry about the byte-boundary stuff at all. You'll probably need to set the segment to be the length of the file, though (or 10 hours or something absurdly long to support live TV recording/rebroadcasting). But who cares, because JRemote can just re-request via MCWS if it "runs out" of stream and hits the end.
Yep, that should be easy-peasy. Set the segment length to the duration of the file (not the stream so-far, but the whole file, you know how long it is except live recording maybe), and send it...
EDIT: I took my previous post out (about recording byte-boundaries as you go) as I thought about it and I was wrong again. You don't need to worry about it, I don't think, if you wrap the whole thing in one big one the full duration of the file itself, and use the "regular style" (simpler) M3U8 files.