1 - On the headmaid list, there's a maid between Bess and Aleah, Who is she?

2 - On the Kagabangui's castle I choose the option the bring back the prince's beloved girl, because of this have I blocked the mission "Pregnant Slave"?

3 - At the mission that i send kurohime to orc's camp, i've lost a treasure chest on there, thre's any way to go to this camp again to get that chest?

1. The slave Grime. When you pick to make her your maid, you can find her in the bottom right corner of the sleeping chamber.
2. Yes, the pragnant slave quest is an alternativ path for the problem with the prince.
3. No, the map is only used for those events and can't be entered again once you're done with it.