Does the zakat due date remain the same (Ramadan), or does one wait for a full year to pass on the money, and how is it to be paid: Is zakat paid on the house alone and the money alone, or is the house considered as capital and both are counted as assets, with zakat paid on the total sum?

A house bought with the intention of trade is subject to Zakat (definition) at the end of each Hijri year. Its value should be assessed, and one-quarter of one-tenth (2.5%) of its value should be given as Zakat. Its hawl (zakat year) is tied to the hawl of the money used to purchase it. If the money's hawl falls in Ramadan (definition), then you should assess the house's value in Ramadan each year and pay its Zakat. As for money acquired later that is not a growth of the original capital, each portion of it is subject to Zakat when its own hawl is completed, and it is added to the cash or trade goods you possess. It is permissible to make the hawl of the newly acquired money coincide with the hawl of the original capital and pay Zakat on all your money in Ramadan, as this falls under the category of permissible advanced Zakat payment.