2. You can't repay the loan in advance within one year, but you can consider it after one year. Theoretically, it's not cost-effective to give you advice, because now 4.5% can't borrow money from the bank, you can use the extra money to invest or lend it to others, and you can make money, of course, only for those who have the ability. The interest on prepayment will be less.
3, depending on your situation, there is no down payment directly. Consider low-rent housing or cheap houses. The consequence of portfolio loan is that you basically signed a sales contract with the bank. Yes, but people will be very unhappy. You'll know when you have a house.
The loan interest is always higher than the deposit interest, which makes the bank get huge profits.