You’ d better keep using multiple small capacitors, because using only one may cause problems. For example, if the data gets corrupted, one LED will not pass it on to the next. Or because the wire between LEDs and capacitors is too long, problems like EMI or EMC may occur.
So it is better to use one capacitor for one LED or a group of LEDs. And make the traces between the capacitor and the LED as short as possible.
More reading: About LED Light Assembly You Have to Know