First time Buyer/Investor – Land or House?

Dear All,
Sorry newbie here to everything…so please bear the long post…

We are would be first time investors and reading up a lot of material before we take the plunge.
We have recently purchased a block of land in SE Melbourne(settling next month) with the original intention of building our first PPOR. We are first time buyers and understand that we will be stamp duty exempt on the house that we build as well as eligible for 10k grant.

But in the last few weeks, we have been thinking on the opportunity cost of this and are thinking of not building it yet(and continue renting), but just leave the land for a while and buy a house(in a knockdown-rebuild condition) in the eastern suburb next year (where we would like to live in a few years time), rent it out for a couple of years time and then knock it down and rebuild it for us to live as a PPOR.

The land in SE suburbs could be built after a few years or sold on…

So the question is what are the pros and cons/implications of this approach

1) Can we apply our first time buyer status against the house purchase transaction rather than the land purchase transaction
2) Will we get the 10K grant against the house purchase transaction?

Is this a good strategy as where we are renting at the moment(SE Melbs) is too far of a commute to the city where I work.

Any pointers gratefully received

Val