Mumbai: Street food in Mumbai?
For someone who is not used to street food in Mumbai, I would recommend Swati Snacks.
Mumbai: Sunrise and sunsets in Mumbai?
Try the Bandra Fort at Lands End, Bandra
Mumbai: Marine Plaza Hotel or Trident Narimen Point - and why? Or elsewhere?
Both are good choices. Rooms at Marine Plaza are bigger but it's a smaller hotel. The Trident Hotel - BKC is a much larger hotel with a much wider choice of food and beverages but probably a bit more expensive and a bit more impersonal....
Bangalore: Best ways of transportation around Bangalore?
Depends on budget and destination but probably auto rickshaw is the best for transportation everywhere.