harman deep ji
There is not a doubt in my mind that all of us need to learn more about the classical forms of Indian music. And most of us can do a better job to practice what we know.
If raagmala is part of Sri Guru Granth Sahib, then it must be considered gurbani, the Guru's bani. That poses a problem. Primary source evidence that is needed to resolve this problem is either missing or suspected to have been destroyed. Therefore the only sensible conclusion can be that the status of raagmala as gurbani must be questioned.
Yes - the original Damdami bir has gone missing and we don't know if the raagmala was included. And Madan Singh ji makes an excellent point in response to this observation. IT DOESN'T MATTER ON THE BASIS OF LOGIC ALONE.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/discourses-in-english/6994-entire-raag-mala-last-2-parts.html
The mundavani and saloka seal the Guru Granth, and not because it is argued they are placed at the end. This is a common error of thinking. As if Nanak 10 sealed the granth and then changed his mind. The mundavani and saloka are not there as a back wall to a house and the architect decided to construct an addition a few years later to make room for more thought.
They the mundavani and saloka seal the Guru Granth as a matter of
gurmat.
There is even a case of one hand-written swaroop which ends before raagmala with "Eh bhog Sri Aad Giranth jee hai". If you zoom in on the page you will be able to see it in the image.
Is it logical or likely that Guru Gobind Singh would have added an entire section to the end of the Guru Granth for the purpose of introducing a raag system that is completely different from the system in which Sri Guru Granth is constructed - without any explanation? This again is very unlikely. It would suggest that either he was unaware of the raag system of Sri Guru Granth Sahib, or was stirring up confusion while indulging in an academic exercise.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=6994
Another question that falls into the category of logical reservations. If Nanak 10 sealed the granth, then who dared to add to it?
Is anyone prepared to say that it is the writing of our Gurus, or a sant, bhat or bhagat as approved by Guru Gobind Singh?? Was there any notation anywhere or even an oral tradition coming from his contemporaries that tells us that he wrote it?
My last question should clarify why I am skeptical of sources that you have cited.