[avile]

Are they ethnically the same ?

Yes many muslims of India are hindu converts, but aren't many conquering colonists?
Any Hindu freepers out there to edify me?

[muawiyah]

It's been a long time since any Hindus converted to Islam in any serious numbers ~ centuries in fact. http://www.hyperhistory.com/chart/islamstory1.html provides a fairly decent, though detailed, time-line for the arrival of Islam in India.