Not in most places, because she is your first cousin.
No
no....because she is a sister for you
That would be your cousin so no you can't.
can I marry my sisters daughter
Such a person would be your second cousin, and in most places marriage between second cousins is legal.
Yes you can marry her. She has no blood relation to you. She is just the niece of your brother's wife from her side. It is no different than if two cousins married two women who were sisters.
A Hindu boy can marry his mother's sister's son's daughter if he can support her. This is legally acceptable on a Vivah Sanskar.
yes
can it be an incest if a son and a daughter who are related because of their mothers who sisters marry each other?
It is legal to marry first cousin in India. http://lawcommissionofindia.nic.in/reports/report212.pdf - Page 19
No thats your cousin and shes your blood. So it is not morally right to marry your cousin.
yes
yes you can!