Bear in mind that the way an entity population is supposed to work is by fabricating detail when necessary. The individual histories of people you meet can be made up, incorporating events that affected the entire population into the story. If a dragon attack wounded 200 people, and a guy you meet is from that population, it's a relatively simple roll to see if he was hurt by it. You just have to run some basic sanity tests, omitting events that conflict with others. The same procedure can be run for a person's family, as necessary. The only additional test required is preventing ancestors from dying before producing descendants.
The last remaining factor would be for world-affecting figures to arise from populations. You could just roll every now and then for every given population, to see if a figure arises. Then you just generate them as normal, but skewing the rolls in their favor, and allowing them to interact with other historical figures via wars, ascensions, artifacts and the like. The only problem with this is that their origins will usually be ordinary. Not uninteresting, but ordinary. This could be solved by further skewing their rolls to include motivating factors (such as revenge, jealousy, etc.) in their origin, selected from a palette of events that affected the population. If you track the amount of each motivation within a pop (revenge motivation from attacks, jealousy from superior circumstances) then weigh the fig-creation rolls based on these societal forces, you can make truly compelling characters that represent the circumstances of their people.