Choosing Correct Switching Power IC for 5v 2A Output from 2S Battery
LTC3633 Does the job for +5v and +3.3v Voltage Generation. 

What I learnt from enough RnD is Switching Supply for Production Level Designs and Linear Regulation for Development and Testing (Fast Prototyping Environments where u dont need to worry much about Efficiency).

I am looking into doing a digital control for the outputs now via the LTC1157 where the Vcc's of the Modules can be controlled by a digital 3.3v tolerant pin.