Does this centerpiece sound ok?

On color... The blue is lovely, the pink is lovely... but they are two totally different colors and will not compliment each other well. If you want to use that medium dark blue candle, I would suggest a deeper pink stone. A nice medium magenta would look lovely next to that blue and not be so pale that it was washed out. If you have napkins and bows on the chairs that are navy blue and there is a difference between that color and the color of the candles, it will be very obvious and could detract from the over all feel you are going for. The slight differences you can get away with in pastels are much more obvious in the darker shades, especially when they are right next to each other. If at all possible, try setting up a table with the colors you are thinking and have a couple of other options to change out with. The candles are about $4 and I know that those types of stones generally run only a dollar or two a bag at craft stores. Since you know what colors you want in the branches and that you want to use clear stone in the vase, those can easily be used again for the reception. I am uming you are renting the linens. Most rental companies are happy to lend you a couple of napkins, etc for one or two days so you can try your table settings out. The added benefit to setting up a mock table is that you can sit down, with a couple of helpers, and see exactly what effect your centerpiece height will have on your guests. Remember that people will want to be talking to each other during dinner and you want everyone to mingle and have a good time. People will not talk to people they can't see across the table. This is why restaurants tend to have only one or two blooms in a bud vase. It is narrow and short and doesn't interfere with conversation. Have a couple of people sit down at different points around the table. See if you can all converse comfortably with each other or if you keep trying to look around the centerpiece. If you are able to converse easily with everyone around the table, great! If not, you may need to consider reworking the centerpieces. Spend a couple of dollars now and avoid problems later. It is very worth it.