Hiya oklouise Ok will try and answer all of your questions....our block is not flat, our house is built into the slope so the back half of downstairs and underground which is why those stairs need to provide natural light to filter through. The stairs currently do. Or exist but we were thinking when you walk in left would come up and right down. so if you drive in the garage you need to come up a total of about 13 steps to get to the living areas OK? the pool and entertaining area is on same level as upstairs. Laundry is best upstairs as this is on same level as where clothesline is and all I need upstairs is toilet/powder room. Brick house, plasterboard walls, tin roof. Original entry is up the front where we want to put that master.  

An architect, a building designer or an interior designer (not an interior decorator) should be able to work with you to create a design you love and get the most out of your interior space. You (or your designer) will also likely need to consult with an engineer, or possibly a good builder, regards load bearing walls etc.

obviously there are some "professionals" operating to arguably less than professional standards and unfortunately they contribute to the confusion of the value of what we do, and make it harder for you guys to trust us at the time that you actually most needs us. There is also a significant difference between a Pro who knows what their doing properly clarifying/translating information as required throughout the design process, to having the subtleties and complexity dumbed down for the sake of "plain language" that risks misinterpretation and underestimation of what's involved. I completely agree, it's often made way harder than it needs to be, and I think again it's horses for courses and certainly there are many professionals who would arguably be best utilised for their skills specifically contained to within the professional industry boundaries, yet others who are naturally better at "bridging the gap" and liaising/working/communicating seamlessly with both the clients and the industry. Unfortunately, to the average punter it's very very difficult to distinguish and gauge these critical key differences between the various Pro's.

assuming all the necessary approvals and accurate dimensions my suggestions have minimal wall removal and plumbing changes for 3 living areas, 6 bedrooms, 4-5 bathooms, WIP and, multi family bathroom sharing with or without the extra downstairs guest bathroom...the new laundry includes a chute from upstairs plus hallway for pool change room and access to bathroom and backyard....there's space for extra-large dining tables plus kitchen meals area and servery for the barbq alfresco but, some windows need moving and consider external windows shutters for sunscreening, upgrading all insulation and a pergola covered area to shade and extend backyard seating area overlooking the pool?