Your party sounds like it will be wonderful!!
I think that if your goal is to have a fun, wine-themed event then you don't really need to worry about some of the things that are required for a more formal tasting. I'm guessing that your guests will actually be drinking their wine samples and not spitting them out (?) If so, then their palates will be flagging after about 3-4 wines. I would suggest serving food throughout the tasting and take frequent breaks so you and your guests can enjoy the wines more as you go along. I probably would also taste fewer than 15 wines so that your guests don't get overwhelmed. They can always go back and "revisit" their favorites after the official tasting is over.
I totally agree with above posters that you should pour lightest to heaviest flavor profiles (and bubbles to start always seems to go over well
). If you do, you don't need extra glassware, and your guests who want to rinse their glasses between wines can do so with the water that you're already providing.
Also, if you can, throw something exotic and interesting in as a "bonus wine".
You have put so much thought into this get-together, your guests are sure to have a great time. Lucky folks!