These would be considered, by me, very short cruises. For some reason, you who say they are not much of a drinker, are considering buying a drink package? Are you a tap water drinker, or insist on bottled water? Do you like to sit in a bar on ship or out on deck by the pool? We always have wine with dinner, drink water from the tap, take water from the ship in our container for drinking off ship. It is easy to calculate.

You might want to consider "getting your feet wet" on the first cruise and see how much drinking you do. Lots of non-drinking time while on a cruise, if you participate in activities, and do tours (any drinking while on tours is not part of your package), Contrarily, you are not talking about a large sum of money.

Most cruises have meet and greet events for singles. Sitting at larger tables for meals also adds to the number of people you will meet. Immerse in activities. Enjoy your cruises and try not to worry about these kinds of details. A cruise is time to relax and let it happen.

Visit Cruise Critic "meet and greet" sections for your specific cruises. This is a way to get to know some people before you even get on the ship! There might be a group of people who have set up a mingle party on ship for you to join.

That's my suggestions on your 2 base questions.

Welcome to FT.

Have a great time.