How many glasses should i put on the table?

There should be an additional glass for beverages along with the water glass. Usually the staff will serve the champagne when it is time for the toasts.

How will people get the champagne or the water or the other drinks? Will they just be on the table? Is there an area to ask a waiter or bartender to serve them the drinks? If they are in cans or bottles, I don't think you need cups for them. We had a full open bar with a champagne toast. Water goblets were on the table, filled, for guests when they sat down and carafes full of water were on each table for refills. Other soft drinks & alcohol guests got at the bar, so glasses were up there. Champagne was served by waiters right before toasts.

You should ask the venue. But I’d expect them to have a bar set up for soft drinks— I can’t imagine them coming around to each table with every different type of soda/beverage option. I would have a glass of water and a glass of champagne at every seat, and if people want some kind of soft drink, have it set up so they can go get it themselves (id have glasses at the soft drink bar for those beverages, but wouldn’t put an extra at every seat)