English can't be considered a Romance language unless you completely wipe out Old English and replace it with a variant of Norman called 'Anglais' (which would have considerable OE/Germanic influence).
I only said that would probably happen if the Marathas embrace European-style nationalism. If the Marathas don't embrace European-style nationalism, then there is no need to enforce Sanskrit upon everyone. You're forgetting that Indonesia was colonised until the 20th Century; a Maratha-dominated...
1: Most likely- but that would only happen if the Marathas fix their administrative system and modernise their economy.
2: I don't think that would be the case. Instead, you'd have various European powers trying to curry flavour (pun not intended) with the Marathas- vying to get the best trade...
Good question. I'm slightly more inclined to say the Mughals as they had an efficient bureaucracy. Unfortunately, the Maratha bureaucracy was a bit of a mess and they relied too much on pillaging (plus divides starting springing up later in the Empire). If there's one thing I'd love to see...
AFAIK, the Chhatrapati was reduced to a mere figurehead. By the time of the Third Battle of Panipat, the Empire turned into a Confederacy, with various nobles controlling parts of the Maratha domain.