Port Wakefield - affordable home - lightweight construction. house design

I have a unique project in country South Australia and I’m looking for someone who can think out of the box and help me obtain a building approval. My unique dilemma is that I have purchased a block of land from a development that went broke and it has an existing concrete footing on the land. I have the original floor plan design but cannot use the previous builders design for obvious reasons. I am looking for someone who can design something else to fit on the footprint of the existing slab. The slab was poured for brick veneer construction, (Concrete raft footing ) but I would like to build light weight, as an owner builder. I am prepared to use unusual and different types of building materials and will sub contract each trade as an owner builder. The engineering issue I face is being able to provide a letter to the local council that the slab is OK to build on, so preferably private certification. I’m expecting there is a lightweight style of construction ( steel frame and lightweight cladding?) that could be built on the existing slab – being substantially lighter than brick I'm hoping the existing slab can be used and I can get certification to satisfy council. I have attached some information – floor plan and photos of the slab, original engineering inspection and engineer report for protection of slabs. I have also attached community scheme description, ( clause 7 etc) shows design guidelines for materials.