EsliEsma
Honestly a Basilisk faihtful to her would be a great new partner, but it would demand years to grow and live for centuries after her death. I fear Rowan won't keep it even if she uses her Parseltoungue to hatched it (given it might be the key to hatch the egg, of course). Leave in the wild is probably another no, so... I am betting on having it become Nadira's companion.