It might depend on where the seeds are from. Nelumbo nucifera is a native here and the colours range from whitish to pink and a slightly darker red, so that will be in their genetics. If the seeds come from a natural population then any of those colours might express themselves in the seedlings. If they're from cultivated plants where the colour range is limited then there would be less likelihood of variation from the parent. With Nelumbo nucifera there's always a bit of an element of a roll of dice.