Parda From Transgenders
There is no such concept of parda which is in practice in some eastern societies according to which, women go in hiding or cover their faces when face a na mehram. Quran in sura noor verse 30 and 31 has delineated the manner of interaction with na mehram. it is that when women have adorned themselves, they need to cover their adornment except for what stays usually bare, leave it bare, like face and hands. It implies that if they have not adorned themselves they need to just guard their gaze and their private parts. (see the verse 24:30-31) Transgenders are like na mehram like men and should be interacted accordingly.
Please also refer to the following thread which contains two detailed discussions with Ghamidi Sahab on the said matter: Discussion 43478