Did you know every blueeyed individual can be traced back to a single couple in UK?

>genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blue-eyed humans alive on the planet today

Having said that, ideal would not so much how many people but how diverse of a gene pool can you get?

Then add in human intervention ie. CRISPR if possible to then do gentle mutations to ensure the diversity keeps growing instead of shrinking once procreations starts.