TCAS
The TCAS gets its altitude from the selected transponder. The transponder gets its altitude from its selected ADC. ADC altitude is separate from ADC airspeed, whose source was apparently flawed. There is no reason for the ADC to fail its altitude output if its airspeed input has failed.
Hence, the TCAS Fail is unrelated to pitot problems, and still a mystery, in my alleged mind. The BEA report said the same.
GB