Inheritance and renting out a property

Hello,

My family owns a house in Spain, which we want to rent out.

The house was owned by four family members split between my granny, mother, and two aunties. My late mother died in 1993 and it is only recently we have found her will indicating that myself and my brother are to inherit her part of the estate.

Two questions;

1. Do we need to pay inheritance tax after all this time, and if yes how much is it likely to cost both in tax and legal fees to carry out? I estimate the property to be worth around 180.000€

2. Can I rent out the property with the family's permission and sign the tenancy agreement as 'owner' although I am not yet on the deeds of the property?

Thank you in advance.