How about a water feature? Inspiration.

I would look at a colorbond exterior broken up with other material. Skillion roof would be the cheapest.

super insulated corrugated iron or modern fibro are good cheap external wall cladding but check out cost of cladding including all labour and suitable insulation to compare values..then, research local council and check any covenants then you need a floor plan designed to suit the orientation and outlook and trades wages cost the same to install cheap materials so aim for products that can be DIY and/or are quick and easy to install so that savings in materials are not used up in extra labour and don't just reduce the size of all rooms, a house with 3 good sized bedrooms and space for an extension is much better value than a house with 4 small bedrooms and no room to extend without destroying something else

once you identify any structural issues and considered advice from an engineer but i suggest that the bricks were probably never meant to be exposed and the render was part of the structure...,is it a single or double brick wall, is there an internal framed wall, what about insulation? depending on the look you prefer it might be better to add external cladding eg corrugated steel or Scyon weatherboards to allow for an air space to improve insulation as well as weather proof the building after the wall is made structurally sound