How is Zakat on money calculated for a property built for sale, given outstanding installments, unsold units, tax expenses, and residential apartment installments? Are taxes and residential apartment installments deductible from the money subject to Zakat?

You must calculate your wealth and your share in the commercial apartments and pay Zakat on them when a full year has passed. The installments you have not yet received can be included in your Zakat calculation with your wealth, or when you receive them, for the past years. As for debts, the majority of scholars hold the view that they should be deducted before Zakat, while the new opinion of Imam Shafi'i is that they should not be deducted, which is the more cautious approach and better for fulfilling one's obligation, whether these are installments or taxes.