All perfect praise be to Allah the Lord of the Worlds. May Allah`s peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Being fair and just to wives has two aspects:
First: Being fair and just to all of them in terms of spending and overnight stay. This is possible, obligatory upon husband and the key condition for having multiple wives in the first place. However, if he can`t be fair and just in this regard, then one wife is enough. This ruling is based on the verse in which Allah says, " If ye fear that ye shall not be able to deal justly with the orphans, Marry women of your choice, Two or three or four; but if ye fear that ye shall not be able to deal justly (with them), then only one,"{An-Nisaa}. Nonetheless, if the husband marries multiple wives (Up to four) but fails to deal justly with them, then he has committed injustice, which is forbidden by Allah.
The husband must be fair and just to his wives financially according to his ability for this is required by Sharia.
Second: Being fair and just to all of them in terms of love and inclination, however, he won`t be held responsible for things that he has no control over, such as love, affection, and self-comfort. The husband is allowed to have multiple wives even if he can`t be fair and just to all of them in terms of love and affection. However, this is provided that this doesn`t affect the first aspect mentioned above (Fairness and justice in spending and overnight stay). This is attested to in the following verse, " Ye are never able to be fair and just as between women, even if it is your ardent desire: But turn not away (from a woman) altogether, so as to leave her (as it were) hanging (in the air)." {An-Nisa`, 129}. Here, "leaving her as it were hanging in the air" means that she is neither married, divorced nor widowed. Clearly, this verse forbids being unfair and unjust to wives in terms of spending and cohabiting because of being biased or even inclined and preferring one wife over the other.
It is an obligation upon husband to provide each wife with a separate residence that fits her social status. This can be achieved by registering that residence in her name or her living in it. This is because she is entitled for housing, but not to have a house registered in her name. Moreover, the husband isn`t allowed to make his wives share the same house as this causes trouble and ignites hatred. However, he is allowed to make them live in a house with separate rooms or floors and separate facilities. It is stated in {Moghni Al-Mohtaj, V.4:417} "If the residence contains separate rooms and facilities, then it is allowed to make co-wives live there without their consent."
In conclusion, it isn`t permissible for a wife to stipulate that the husband gifts her anything, without his consent, after the conclusion of their marriage contract, but before the conclusion of contract she may stipulate anything since fairness and justice between the wives is required after conclusion of contract; not before that. In addition, it is recommended for the husband to be fair and just to his wives with regards to gifts that exceed the limit of obligatory spending required by Sharia. Thus, if he wants to gift something special to any of them, then he is free to do so for he can sell, buy, and gift what is his property. However, this is provided that he doesn`t do so with the intention of harming and depriving the rest of the heirs since, if this is the case, it is forbidden. And Allah the Almighty knows best.