The original 9X, with er9x firmware, once it had the telemetry mods and the voice module I designed added, does all those things. OpenTx was forked from er9x some time ago, but many of the basic concepts are still the same. In particular, the mixer was originally designed by Thomas Husterer, who deserves far more credit than he generally receives. It was he who wrote the TH9X firmware with the mixer in. Erazz took TH9X and forked er9x, and later I added to er9x.
Before the Taranis, there was also the Gruvin and SKY board upgrades for the 9X that provided a much easier upgrade method for the 9X to provide these extras. Having modified er9x for the SKY board (ARM processor) I was able to quickly write the low level drivers for the Taranis, much of which is still in the current firmware.
The Taranis and the firmware have just made this more accessible by being sold complete and ready.
So please remember the history, and provide credit the originator "Thomas Husterer" for currently used concepts.