EB =elite boutique like Lazard, BNP Paribas etc BB = Bulge bracket like GS, JPMorgan, Citi etc.

Been on a internship at an EB-bank. I didn't drink and I could join their AWs and all without a problem. Got some neutral questions about my non-drinking and then it was out of the world. Mainly because when I drink I make a fool out of myself and doing that with potential future colleagues is a big no-no. My answer was I need to quit my bad habits like smoking and all. Never brought up religion.

I don't have any (ex-)muslims that have done a internship at a BB, like I assume you do. But one friend, who had alcoholic parents and was afraid of taking a sip because genetics, said they were cool. But it's really different from bank to bank. I don't know about all of them.