After your full set of documents are received, 3 to 4 working days for employed individual and 8 to 10 working days for self-employed individuals. It can vary if banks need some clarifications.

For most of the bank pre approval is valid for 30 to 90 days however you can revalidate the same after submitting latest documents to the same bank.

Yes, they can, however, T&C for non-residents will be different and the rates may be slightly higher compare to resident mortgage.

Most banks will calculate affordability slightly differently, but a general rule of thumb is that they will take only 50% of your monthly income into account when calculating this. From this 50% they will then deduct any other credit commitments you have (e.g., car loans, personal loans and approximately 5% of all your credit card limits), to work out your maximum affordability. They will then carry out a stress test by applying a stress rate of interest which varies between 3.5% to 8% depending on the bank. The aim of this is to confirm that you will still be able to afford your mortgage repayments if the interest rates were to increase to the test level.