Which is a good way to do that, I won't disagree. Probably a little more complicated (or should I say, Advanced) than I think WotC would like, but certainly a good method. However, none of them have a dedicated half-elf race anymore. That concept is dying. The question has become what is the best method to emulate mixing, be it trait mixing, feats or purely RP. And we can all disagree about which is best. But I can no longer fault WotC for removing them as dedicated race options since LU, TotV and PF2e already had.