I know that you have dead lions that were once part of a hunting party italic. Well for me that makes me think that it is a broodmother or that it is pregnant.

Like with the PH(Primary Hunters) hunting party I have Moja Giza, Golden Fire, Moja Mwanga, Simba Dhahabu, and Rangi Moja. None of these lions are pregnant or broodmothers. Moja Mwanga is dead. All the other primary hunters are 14-16 years old at level 9.

So my suggestion for the hunting party is to have dead lions automatically erased from the hunting party member list.

As for lioness levels they don't gain any stats from leveling up, just from hunting and occasionally food. I think that they should gain stats from leveling up and that the number of stats they gain is dependent on these factors:

1) Total hunts(More hunts = More stats)
2) Success rate(The more trouble the lioness has had, the more stats she gains)
3) Current level(Low level lionesses gain more stats than high level lionesses)
4) Total EXP before leveling up(The more EXP, the more stats)
5) Current stats(especially skill, like low skilled lions gain more stats than high skilled ones)

As for the formula I don't know what it should be.