From what I remember, there will be plenty of choices for your vegetarian friends.. My friends really enjoyed the pasta dishes as well as other stuff.
Your vegan friends will find it more difficult.
Life is too short to let the ship of your dreams sail without you.
Carnival Destiny Feb. 2006
Carnival Fascination Feb. 2007
Royal Caribbean Grandeur of the Seas Feb. 2008 The DTW & MsBJ tour
Carnival Valor MsBJ and Dina Feb. 2009
Carnival Glory MsBJ and Dina Feb. 2010
Carnival Dream MsBJ and Dina Feb. 2011
as a vegetarian who only cruises HAL I've found their vegetarian selections to be excellent. They always have at least one vegetarian choice for each course on the main menu and you can also ask for the next night's vegetarian menu and pre order anything you want (my non-veg friends frequently joined me--the food is excellent). The items on it are clearly marked vegetarian. I honestly didn't notice the amount of vegan offerings but I'm sure you can call the customer service number of the cruise line you're interested in and inquire.
"you've got to spread your arms and hold your breath, and always trust your cape"