The THR22 hardware is the HR22 so whatever holds for that is still the same.
You can use two outputs from the WB616 to the THR22 for the two tuners. Yes, you'll need BBC's.
The THR22/HR22 also support SWM. In that case no BBC.
You can use two outputs from the WB616 to the THR22 for the two tuners. Yes, you'll need BBC's.
The THR22/HR22 also support SWM. In that case no BBC.