Frankly I don’t understand why you think you cannot use OH2 with the Insteon plugin.
I still use OH1, but installed OH2 to see if the insteon plugin didn’t work. I configured it exactly the same as the docs explain for OH1 and it worked immediately. No issues at all.
Now, I do agree that there isn’t a nice OH 2 front end GUI config, but it doesn’t require special developer knowledge to do this. Just the same config as everyone who ever used OH1 did.
I think it’s cool that you’ve made this bounty to take the OH2 Insteon experience to the next level, I personally don’t have the skills to do that. Hopefully someone out there does. I did just want to make sure you that Insteon is perfectly usable in OH2 now.