Firstly, I'm a newbie, so my apologies to all!

I have just purchased a 3/4 acre property in the Sunshine Coast Hinterland
(Qld). About half of this property (say 3/8ths of an acre) is just lawn
which I would like to turn into a mini-orchard. The only problem is that I
can't work out how to plant this mini-orchard.

You see the part that I want to plant is a triangle shape. It is also on a
very slight incline.

Here are some of my questions?

1. Should I plant all one type of tree or do I need to companion plant or
do I just do it higgily-piggily?
2. Should I plant along the incline or straight up and down?
3. I'm leaning towards planting mango's and macadamia nut trees (about the
only things that we all eat), but how many trees would be too many?
4. Can you successfully grow peach and plum trees in my climate?
5. Should I go in neat little rows, or just plant them all over the place?

I think it's important to get it right first time, so please forgive my
stupid questions.

Regards,
Lynda