Is it permissible to pay the expiation of an oath to a charitable party as it feeds the poor and needy such as Tkiyet Um Ali?

All perfect praise be to Allah, The Lord of The Worlds, and May His Peace and Blessings be upon our Prophet Muhammad and upon all of his family and companions.

There is no harm on authorizing someone to handle the expiation of another to the poor and needy, since Shafiee's jurists stated that authorizing someone for the purpose of distributing Zakah, expiation and vow is permissible as stated in [Mughni Al-Muhtajj, vol.3 pp.237]. At last, the intention of the person who intends to authorize someone else suffices in this regard. And Allah Knows Best.

What is the ruling on combining prayers at the Musala (Place for prayer) of a shopping center because of heavy rain, knowing that some people come from outside that center?

Praise be to Allah, the Lord of the Worlds. If there is hardship in going back to that Musala at the time of Asr or Isha` prayers, then it is permissible to combine prayers (Duhr with Asr and Maghrib with Isha`). Kindly consider calling us. And Allah knows best.

Is it permissible for a woman to uncover her face while performing Umrah(minor Hajj)?

The woman who is in a state of Ihram(ritual consecration) should uncover her face and hands, but it is permissible for her to let her head-covering garment drape from her head down over her face when non-Mahram (i.e., marriageable) men pass by her.

Is Zakah(obligatory charity) due on owned land?

Zakah is due on the land used as an article of merchandise and was originally bought for that end. Zakah is due on it at the end of every lunar year. Its value is estimated, and (2.5%) of the total value of all such lands owned by the questioner is given as Zakah. However, no Zakah is due on the land used for building a house, or an agricultural purpose.