Do you mean plans for construction? There are many sites on the Internet that will have samples for you. The main issue is that local ordinances require setbacks from property lines and these free samples may not fit what your local building department may require. You can usually access the setback information from your building department online, but a trip down to talk to a planner may be necessary. Start there, finding a house plan that fits within that footprint is the second step.

I like the little square windows but wondering if they are properly placed inside and will they offer light, views from seating area, ability to open and allow fresh air in? Besides the design also consider how they will be used.

You need an architect

A rule of thumb is that the distance between the house and a eucalyptus should be 2/3 the height of the tree. So if the tree is maybe 45 feet, you'd want the house to be a little over 29 feet away. As well as any new root growth that could affect your house, cutting into a root system compromises the stability of the tree. Also, even if the existing roots are deep, driving over the area with heavy construction machinery could compact the soil enough to affect the health of the tree. That's not to say that you shouldn't try, just be aware in case it becomes necessary to cut the tree down later. Good luck and enjoy your new home!