Is it permissible for a girl to wear colored contact lenses?
All Perfect Praise is due to Allah, The Lord of The Worlds.
Wearing colored contact lenses for medical treatment is permissible, and wearing them as an adornment is also permissible, provided that she isn`t seen while having them on by non-Mahrams. And Alalh Knows Best.
What is the ruling on obtaining a house through the King Abdullah II project (Decent Housing for a Decent Living), knowing that we do not own a house, our financial situation is moderate, our current rental costs are high, and we are eight people living in the household?
If owning the apartment/house is done through the same institution/project then it is permissible, but if this took place through usurious banks then it is impermissible, since dealing with usurious transactions is unlawful. And Allah Knows Best.
Someone asked me to pay off his debt on his behalf as a loan, without any compensation. When I went to the creditor, he told me that if I paid the full amount at once, rather than in installments, he would give me a certain discount. Is this permissible? And if he applies the discount, to whom does the deducted amount belong?
If part of the debt is paid and the creditor forgives the remaining amount, the waiver is valid, and the remaining debt is no longer the responsibility of the original debtor. The person who paid the debt on behalf of another has no right to claim any portion of the original debt. And Allah Knows Best.
Is permissible to buy/sell with non-Muslim?
Yes buying/selling for a Muslim with non-Muslim is permissible as regards what is lawful.