In terms of the assessing the appropriateness, this is something for you to decide, based on you understanding of the stakeholders and end users. There is a lot of great information and resources on the challenge website that will help you understand that in greater detail. Also, a big factor in the appropriateness of your structure lies in its suitability to the climatic and environmental externalities on the Peninsula.
For the implementation plan, you should be considering what is required to get this structure from the page into the field; what kind of personnel is required for assembly, what materials are needed (are these local or trucked in?), what are the general logistics?
In terms of having specific suppliers and knowing exact pricing, this may be difficult to find with the time you have, so it would be ok to make a few assumptions around costs.
EWB Australia acknowledges the traditional custodians of country throughout Australia and recognise their continuing connection to land, waters and community. We pay our respects to them, their cultures and their land; to Elders both past and present; and to emerging leaders. We recognise that the Aboriginal & Torres Strait Islander people never ceded sovereignty of what we call Australia.