Re [7] and the MiNT kernel/OS:
If you're interested in running MiNT on your old Atari hardware (or emulator) then https://freemint.github.io/ is the project website.
And if you want to run it on the Aranym emulator then EasyAraMint is a good place to start: https://sites.google.com/site/beebox68k/operating-system/os/...
I only recently tried FreeMiNT for the first time. It's a really weird feeling to come back to the Atari platform and see something that looks familiar but has been updated and dragged, if not into the present day then into the late 90s at least. Gone is most of the CP/M heritage of the original TOS; instead, it's a UNIX-like OS with a lot of the GNU userland. For me, using it is exciting like using Linux in the late 90s was exciting. It just leaves me feeling rather sad that Atari exited the computer market before the OS was quite ready and the community had to finish the job.
(And if you're wondering how this is relevant to EmuTOS, well, EmuTOS is used as part of the boot process.)
I have no idea if it's in any way viable, but something it would be immensely cool to see is some combination of Emu68 (or some other bare-metal emulator) and EmuTOS and FreeMINT, some combination that made it possible to run FreeMINT directly on a Raspberry Pi as the OS.
Not in an emulator under Linux. As the only OS.
ISTM that even a $5 Raspberry Pi Zero should be more than powerful enough to run this well.
I confess I would really like to see EmuTOS and/or FreeMiNT running directly on the Raspberry Pi, though I suspect it would be a huge amount of work. Right now, if you want Atari compatible hardware, you can either pay $$$$ for a vintage machine (and replace all the capacitors), or you can get something like a Vampire V4SA and put in a lot of effort to make it work run anything.
Raspberry Pi is a really nice (and relatively simple) hardware platform that would be great for running something like this and I have thought about it myself. Something like adding ARM [32|64] support to the kernel and then using an emulator of some sort to run 68k usermode programs. But I don't think FreeMiNT has ever been ported to any other architecture and imagine it would be a _huge_ effort.
The way Apple moved classic MacOS from 680x0 to PowerPC was to write a tiny kernel emulator, with an API to run native stuff on the metal, and run more or less the whole OS under emulation, profile it and just translate the most speed-critical bits.
https://en.wikipedia.org/wiki/Mac_OS_nanokernel
That's a lot of work for a FOSS project but given the performance delta between 1980s 680x0 and 2020s ARM, total emulation of the whole thing should be perfectly fine. It's how the PiStorm Amiga upgrade works.
https://amigastore.eu/853-pistorm.html
So all I envision is something like Aranym:
... running on top of Ultibo, say:
Or maybe Circle: