Avoiding interest on PPOR

Can you help my muddled head.

We recently bought land in the name of our family trust to build a dual dwelling and keep for 5 years to avoid gst on the sale. The LOC was slow coming so we had to use our own funds to buy the land. ($128k)

We now want to buy land for our PPOR ($215k). We have no debt on our present PPOR and can get a LOC of $504k to fund new PPOR.

We can draw down $128k from the trust LOC to reimburse us for the one month we lent it the money. This leaves the investment project at 100% lend.

We then have $160k cash towards buying PPOR land. Construction costs for PPOR will be approx. $280k. We will need to pay interest on $335k to complete.

Both projects are going to take about 18mths to complete.

So my questions are:-

1.Do you think 2 LOCs is the best way to fund both these projects or variable with offset?
2. Would it be best to sell present PPOR now and rent so there would be no interest costs involved in building next PPOR? Moving twice is not appealing.
3. Have I missed anything I should be considering?

To save on non-deductible debt should be sell our present PPOR so no loan would be needed to construct next PPOR
about the only way you're going to minimise / eliminate inteest on your PPOR is with a 100% mortgage offset account.

keep the cash, reap the benefits, sans the fees of an LOC or redraw facility.