Design and plans for home renovation

We have recently purchased a property in Melbourne and are looking to have plans drawn up for a renovation and extension. We require sketches/ rough drawings before deciding how to progress further. Our scope is as follows: • Minimum 4 bedroom, 2 bathroom residence, with separate study, formal living, and open plan living/ dining/ kitchen • Maximise living area to best make use of space and site orientation • Priority is internal living space, followed by useable outdoor space (maximize grass area, whilst still ensuring adequate area for pool and outdoor entertaining) • Design to be completed with a view to minimising costs, as we will look to sell and realise a profit • Maintain single/ split level • Undercover alfresco/ outdoor entertaining area with shade • Maintain existing residence as much as possible to reduce costs (internal walls may be adjusted to suit design) • Master bedroom with WIR and ensuite (ensuite with bath) • Family bathroom large enough for a bath • Built in robes in other bedrooms • Family room to include fire place + hearth • Double garage accessed from ROW at rear of property • Separate WC downstairs • Walk in pantry • Large laundry • Floorboards in living/ dining/ kitchen • Pool in backyard • Maximise Northern sun • Floor to ceiling glass in living space if practicable • Tall ceilings – min 3metres – higher over living area? • Please consider both an extension that compliments the existing dwelling as well a more modern interpretation (e.g. a box). So basically a pitched and/or flat roof. If a pitched roof, we would most likely look at a tiled roof to match the existing residence