Yes, the Insignia device has the Flash Player. Running an alternative Control Panel is most certainly allowed.
We would have an issue if someone distributed a firmware image or something that had the Flash Player embedded, since our distribution license with Adobe does not extend to anyone else.
We'd also have an issue if someone redistributed software that contained our trademarks, such that it gave the impression that it came from us instead of from the third party.
I think there are other firmware differences between the Chumby 8/Opus and the Insignia 8", so I don't know how well the Opus Control Panel would play on the Insignia device. You are welcome to try, but just be aware that it's not a combination we officially support, so the responsibility is yours.