Regarding speaking in the restroom

Shalom uverachah, 

One should not speak in the restroom, because it is considered a lack of modesty (Rama, Orach Chaim, siman 3, section 2). In any case, it is permitted to answer a phone call if one fears there may be an issue of financial loss, or some other great need, but one should shorten one’s words as much as possible (Yabia Omer, vol. 8, Orach Chaim, siman 1). 

With blessing, 

Hillel Meirs