No IRQ between TLA sensors and FADEC ?
No. The position information is transmitted by 6 cables per sensor, which allow to cross-check for cable breaks and potentiometer breakups for each sensor. These analog signals are fed into one channel of FADEC (A), the other 6 from the second sensor are treated completely separate in channel B. The arbitration between the two FADEC channels takes place after input check and evaluation of the signals. Each channel is capable to control the engine on its own if the other fails. They are independent, also physically, which means that every chip is only responsible for one of the two channels.
Once again, this is no cheapo hardware like just one microcontroller doing all the math, so there is no need for such constructions like IRQs.
The engineering is well aware of the importance of treating these things right. Also the test departments are very creative inventing scenarios the engineering departments might have overlooked, kind of competition. Trust me, I have worked in that business, although not especially on thrust levers and engines.