How does the in game randomizer pick variants?

Does each variant have the same chance of being chosen as a hero without variants (EG, do Legacy and Young Legacy each have the same chance of being chosen as Ra) or does each hero have the same chance of being picked over all (EG, all forms of Legacy combined have the same chance of being chosen as Ra, if Legacy is chosen, it then does a separate randomization for Legacy or Young Legacy)?

It picks the hero randomly without considering variants, then randomly picks between available variants.

Thank you!