Rebuild IP, live there and rent out current house

I'm a bit naive when it comes to finance/tax matters so I thought I'd run this past more knowledgeable people for any comments.

Soon will be retrenched. I'm around 60. Good payout and already fair amount in Industry super fund.

Will have a (taxed) pension, so will have a strong cash flow in retirement.
Plan to knock down current Investment Property and rebuild there with aim of going to live there and rent out our current home in Sydney.

Current plan is to increase our borrowings to pay for the rebuild rather than to take money out of super.

New build will include a 'granny flat' which we aim to rent out as well.
So even though we will have a high debt we will be able to pay interest out of the pension, plus money from the super fund plus rent for granny flat and rent from the Sydney house.

I'm comfortable with all of this but was just wondering about whether anything should be set up differently.
Things like - should I set up SMSF and borrow for the rebuild through that. How maximize relief on interest if any is possible (noting that main income in retirement, the pension is taxable)

If you were in this position what alternative ways of doing things would you at least consider?
Many thanks for any comments
 
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