How does Capital Advisory at Elite Boutiques work?

I have a natural interest in M&A (valuation etc) and would love to be a 'lifer'. However, my religion prohibits me to work with interest and debt. This means working at BBs are off the table as they're underwriters however I am curious to how it works at EBs? I've been told although EBs dont underwrite the debt, they do all the heavy lifting for the client? I would be comfortable with just advising the client where to get debt from, but if I'm holding their hand in the process, then I would be against. 

Furthermore, at small EBs like Centerview, PJT etc I understand early on youre a generalist. But is there an opportunity to just work on the M&A side? 

I interned at a BB last summer and got an offer, but whilst I worked in an indsutry M&A group, there was some support to the Debt team (esp if the client was a newbie) which made me felt uncomfortable and I declined. 

Any advice particularly from those who work at such firms would be much  appreciated. 

I am based in London if it helps.