TOURNAMENT CLARIFICATION: SPARES WITHOUT HEIRS
It is legal to have a generation that doesn't contain an heir; the "spares" of this generation may still make lifts as normal. (The most common case for this would be a prestige occult where the babies are not born of the correct species).

Note that this will be your last generation. If that's sufficient to lift the last of the restrictions, all good - otherwise, your challenge will end as none of your spares can produce the next generation you'd need to continue.