Duplex Construction Loan and Process for New Purchase

Hi there, I’m a current home owner looking for advice/insight on the financing aspect of purchasing land and an existing house, splitting the title to build 2 duplexes, and then selling one immediately (ideally for some profit or to at least cover costs and live in a new duplex)

While I’d have enough deposit for 80%LVR for the land and existing house purchase based purely on savings, I doubt I’d pass any banks’ assessment of being able to service this AND a construction loan over the long term (see example numbers below), and would this be selling the second duplex right away….or a bit down the track to avoid CGT if possible.

As such, I have 4questions based on these hypothetical numbers (excluding title split, stamp legal costs etc)
Land and existing house purchase price:
1.5 million.
Duplex construction: 1 million
Cash deposit available: 500k (plus additional savings to cover 1.5 years of loan payment/ holding costs etc, but anything past this could be a stretch)
Total loan needed 2 million

Question 1: When buying an existing house and land to knock down and build 2 duplexes in Australia with intention to sell one, do you I get one big loan up front with a portion of it being a “construction loan” which would be drawn on construction stages or is the only way to get 2 loans: one for the purchase of land and existing property and then, apply for one of the construction of the duplexes.
For example.
Loan A: 1.2 million for purchase, then apply for loan B. 800,000 for construction.
Main concern is that bank would refuse the 2nd loan if they don’t trust that I will sell one of the duplex’s to pay back that portion.

Question 2: Is it common/possible to get such a loan on the condition that you will sell one of the duplexes property to payback the loan? I ask because I would not be able to service the loan long term and would sell one duplex to pay down/off one of the loans.
Question 3: Do construction loans (or the portion of a loan that is deemed for construction) require the down payment, or can I put down 10%?
Question 4: any way of avoiding CGT when I sell one?

Thanks in advance for any valuable insight, advice. Need to assess financial process and feasibility before next steps!
-B25