Question:

How accurate are the isnaads (chains of narration) written for the Durood Taaj, Durood Lakki, Dua-e-Ganjul Arsh etc.?

Answer:

The isnaads (chains of narration) for the Durood Taaj and Dua-e-Ganjul Arsh are baseless.

(Grand Mufti of India, Hazrat Mufti) Muhammad Kifayatullah Delhi (May Allah be for him)

Kifayatul Mufti Vol.2 Pg.99
Durood is to send salutations (الصلاة والسلام) upon the Messenger of Allah (صلى الله عليه وسلم)
Also see here and here.