He is reliable? Print is balanced?Did you read the article? It clearly references China's perceived LAC, not claim line. Keep in mind this is from Snehesh Alex Phillip, one of the most reliable defence journalists in India. The Print is also a balanced source.
Indian army officials generally have a decent idea of what China perceives its lac to be based on PLA patrolling patterns and intereactions with between local commanders, though the exact extent of China's full claims have not been shared with regards to the Eastern Sector. However, we know China does not even recognize Ladakh as India, which gives a hint as to how much they claim.
Not to a foreign observer.
There is nothing in that article that states as to the actual LAC of China. The "perceived LAC" is soon followed with the phrase "Claim Lines". A clear distinction between the two is therefore not made there.
To put it simply -
If China reaches Burtze, wouldn't its Claims be satisfied? Anything beyond Burtze is the DBO road.