I don't know exactly what starburst polyps are, but I am assuming that they are some form of zoanthid, or other similar soft polyp.
As for when they will open....the honest answer is that they will open when they are good and ready! Unfortunately, most animals do things according to their own speeds. You have recently moved the animals from where they were, placed these polyps in a new tank, with different water than they are used to, at a different temprature than they are used to, with different lighting than they are used to, with different flow rates, and current patterns, etc. (you get the idea)
Assuming that you properly acclimatized the polyps (salinity and temprature), and assuming that they like the lighting, flow, and current, where you placed them, then they will eventually open.
I have had polyps open within about 10 minutes, and others have taken upt to two weeks...no idea why.
Don't stress, I am sure they will be fine...but there is no way to get them to open in time for your friends unless the polyps want to.
Also, you may want to wait a day or so before you bump your own thread...it will generally take people longer than an hour or two to actually reply etc.
Stewart