Findabair or Finnabair (modern Irish Fionnabhair ] ) was a daughter of Ailill and Queen Medb of Connacht in Irish mythology. The meaning of the name is "white phantom" (etymologically cognate with "Gwenhwyfar", the original Welsh form of Guinevere). The Dindsenchas also mention a Findabair that is the daughter of Lugaid Laigde.
Can we infer the following?
Findabair was the only daughter of Ailill 
It's impossible to say