I had a query on Namaaz Washat. Is it recommended for Wali of deceased only or can anyone recite it. If anyone can recite it, what would the Niyat for it be? If Namaaz Washat is not a sunnat Namaaz for all and only for Walli, then can Namaaz Hadiya Mayyit be offered instead?

For Namaaz Mayyit, from what little I know, it is to be recited by one person. Most of us follow the imam and don’t say anything or try to recite with him. What is recommended? And if it is recommended to be recited alongside the imam can one read from the phone?

Namaz e Wahshat is a recommended namaz for all there is no restriction that only Wali has to recite this namaz. Anyone can recite this namaz for any Muslim and Niyyat would be that particular deceased person.
As for as Namaz e Mayyet concern it is a Wajib Kefayee for all Muslims to recite namaz for a Muslim. We should not keep silent while everyone has to recite if he knows what has to recited otherwise he/she has to repeat while Imam is reciting. If anyone does not know he may recite either from phone or paper etc.