Love the Tinman fabulous!!

my suggestion are based on the fact that mum and dad are usually at the house alone and aims for simple two person accommodation that can be rearranged to suit a crowd...the kitchen cabinets are the only fixed objects in the room and include a tall pantry, base cabinets and/or drawers with open shelves and wall cabinets and space for several people to work side by side with a small extendable dining table, two chairs and a bench seat (also used as a place for newspaper and lamp etc behind the recliners)...a patio with big table for outdoor eating under the shade of the tree with extra bench seats that can also be used inside... there's space for a small divan or night and day lounge with a wall hung tv and the corner bedroom door allows for much better circulation space in both the living and bedrooms with preferably a sliding glass door for indoor outdoor connection with or without the original front door and, based on the size of king single beds, there's no other arrangement that would allow both beds to have a view to the lake and there's just enough space for a biw, small desk and two chairs

You don't mention where in Australia you are or which side of the house faces North this information will mostly determine what you can grow and where. Your block isn't small at all. In landscaping terms it's enormous and will cost a lot of money to put in a nice garden. As a starter..... The facade of your house is imposing, almost out of scale with the neighbours. I believe you will benefit from a medium sized deciduoos tree out the front behind the letterbox to soften the area between your home and your neighbours. Putting it on that side will frame the house nicely and balance the enormous scale of it. Something like a gingko would be lovely. But you need to be in temperate or cold zone for that one. Also the lawned slope is not helping the home sit into the landscape. I would go large boulders and a rockery across this part, not a fence nor retaining wall. Your home is already strongly geometric, a naturalistic strip will work wonders to bed it into the neighbourhood. If you can't stand the look of boulders then gabions are an alternative that look very modern and smart, especially if interspersed with tall ornamental grasses. There are many creeping conifers you can get that will grow in many climates. Once established they need no care but can look amazing. The easiest way to work out a cohesive scheme is to zone the yard into outdoor rooms. This is exactly what landscape designers do. So rather than going well I want a deck here, a bush there and lets just chuck some grasses in here. You end up with well defined area's that each have a purpose and a particular style, rather than random shrubbery dotted about the place. you'll need to cruise the internet a bit to find some landscaping you like. No-one here can guess what modern with character means to you. Does it mean tall strappy things, cacti, grasses? Hedges? It's easier if you can find a general style of garden you like, such as Balinese, Japanese, South Western, tropical etc. Then good old Google can show you every possible version of that from traditional right through to edgy modern versions. Typically anywhere in your yard that is going to get full sun all day will be unbearably hot in summer, you will want some shade there, but probably also want it sunny in winter (depending on where you are). This is where you need to plant deciduous vines or trees rather than evergreens. In terms of your access to the clothesline, the least expensive option will be a gravel path down that side of the house. You can lay it yourself and it only needs some lumber to define the edges and keep the gravel from spreading all over the yard. That won't be any good for dragging wheelie bins over though. You will also need to spend a weekend watching the shadows over the yard and seeing how far they stretch and at what times of the day. Any plant labelled 'full sun' needs a minimum of 6hrs of direct sunlight a day. Part shade plants need 3-4 and usually do better with morning sun and afternoon shade situations. And then there is the tiny group of plants known as 'full shade', don't be fooled. Most of them still need several hours of dappled light. There are really only a handful of plants that can survive full shade proper, so these area's of the yard are better off paved with a container filled with something known to be unkillable like clyvia.

Some comments, I hope they are helpful. Create a gravelled area for your fire pit. Laying a some sand, levelling off, a weed barrier and raking gravel is within the skill set of most handy people. Use treated timber for an edging to keep it neat. Buy a nice ready made steel fire pit. Buy some seating. Your planting lacks a scheme. Without a scheme your yard will not look put together the way professional landscaping does. Every plant has to be chosen for a purpose (texture, height, colour, privacy etc). You also have all your garden beds in a perimeter against the fence. That's fine for a starting point. But to make the place look inviting you need some garden beds in the yard too. Please avoid the common habit of putting shrubs in the middle of the lawn. It doesn't work well and also makes maintaining your lawn difficult. If you want to make say the entertaining area private from the kids play area a full garden bed is usually a better bet than just a shrub or two. By putting multiple shrubs of varying heights and a creeper in a larger section you create outdoor zones and properly define the area. What you really need to do is measure your yard, draw in your house and all paths and then start drawing in the entertaining area, the kids play area, the veggie patch etc. You will probably have to play around with the layout for a while to come up with something you like and works. Trust me, doing this first will save you a lot off $$ on plantings that don't work and you want to remove later. When you create garden beds do it with three heights. So something under 6" tall, something under 2ft tall and then something over 3ft. Not a definite rule but a good rule of thumb. By having multiple levels in your garden beds you create a more impactful and interesting garden. When gardens are meh, its usually because all the plantings are the same height and it looks flat. Take a look at these gardens to see what I mean.... Alright this fire pit is obviously professionally done, but what you need to look at is how the fire pit is clearly separated from the rest of the yard. The seating creates an outdoor room feel. But also if you look behind the seating there is also a large garden bed behind it. Although the scheme isn't finished my bet is that some tall screening plants are likely to be planted there to create a more intimate mood and shade from summer sun. Having garden beds define a feature really works. This is what I mean about having layers in your garden beds. If this yard was just a row of trees along the fence and then say a low hedge in this front bed it would look okay but not great. They have used different colours, textures and heights all in the same bed here to create something much more interesting. The planters in that corner also create height with the strappy plants. This is why you need to plan our your whole garden so you know that all the plants across the yard work together coherently.