1. Buses are more common but they tend to get crowded. Ola, Uber accepts cash, I always use UPI for convenience. Another option might be to get a bike if that's possible.
2. If you are travelling in a bus it might be hard till you learn to understand some common words. You can manage in Hindi
3. This, I have no idea

The best commute depends on point to point. While buses are good, they may not connect all points. There is metro to many places now. Uber ola and rapido accept cash but it may be difficult to book a ride during peak times. Best is to stay close to office. Hindi works for most part. Moreover in Brookfield locals will be a mix of Telugu Tamil and Malayalam along with Kannada folks. Shop keepers are mostly malayalis or marwaris. So Hindi should work. There are a bunch of new PG that have come up behind Bgamane Solariam city in the Ekya ITPL school road. You can check that out. However nearest bus stop from that point is around 750 Meters. Since the PG is newly constructed it might slightly be better.