For one of your table options grouping floating candle vases together is a pretty option for a non-floral centerpieces. To add the "wow", tint the water in some of the vases a dark purple and some a light purple and float gold candles.
Insert a small vase into a larger one and filled the space between them with coffee beans. The inner vase can hold flowers. Or insert a pink candle into the center of a vase and fill around it with coffee beans.
Diva - Table idea for st. patty's day - LOVE the ribbon idea! Patrick's Day Party: a simple and classic St. Patrick's Day table setting - a great example of how to incorporate Pantone's color of the year - Emerald - into your next tablescape!