It's सुरश्रेष्ठ (suraśreṣṭha) – best of the gods (Indra) – as that's what the critical edition (CE) of Vālmīki Rāmāyaṇa uses:
1047020a अथाब्रवीत्सुरश्रेष्ठं कृतार्थेनान्तरात्मना
1047020c कृतार्थोऽसि सुरश्रेष्ठ गच्छ शीघ्रमितः प्रभो
1047020e आत्मानं मां च देवेश सर्वदा रक्ष मानदः
It seems that सुरश्रेष्ठ is right word but second source added few words in the translation from previous shloka's meaning, these words are not in it's word-to-word translation. In first source Vishvamitra addressed Rama with नरश्रेष्ठ which is not needed as रघुनन्दन is already used in previous shloka. Here is the shloka from Gita Press Gorakhpur edition (...
As Ganguli himself explains in the preface to his translation, he used two different editions of the Mahābhārata text, namely, Bengal and Bombay:
I cannot lay claim to infallibility. There are verses in the Mahabharata that are exceedingly difficult to construe. I have derived much aid from the great commentator Nilakantha. I know that Nilakantha's ...
So who was this narrator who wrote the Manusmriti?
It depends on whether you are looking for the traditional answer or an academic (non-faith) scholarly opinion. Based on your citing the example of Vyasa/Ganesha for the Mahabharata, it appears you are looking for the former.
In that case, the narrator of the Manu-Smriti is Bhrigu Maharshi.
If you look at ...
Lakulisha's Pashupata Sutra is the main text of Pashupata Shaivism according to the Wikipedia article on Pashupata Shaivism:
The Pasupata beliefs are summarized in the Pasaputa Sutra. This text was rediscovered in 1930 and is attributed to Lakulisa himself. Bhanmdarkar attributes the Atharva-Sirasto the Pasupatas. Also, in the text, their vow is recorded.
Manu Smriti does not mention whether the laws are composed by someone or not. It is somewhat addressed in the following verse from Parashara Smriti:
Na kashchitvedakartA cha vedam smritvA chaturmukham | Tathaiva
dharmAn smarati manuh kalpAntareantare ||
The author of the Veda there is none ; (he) the fourfaced (God), at
each succeeding ...