I think the first layout is fine. You might want to consider moving the door for the storage room of the master bedroom so that it opens into the hall. That way the kids can use it for overflow storage. Also, that hallway is big enough that I think it could hold a large armour, providing more closet space. (There's no need to sleep in the same room as your clothes, so long as they're not too far off.) Also, don't forget that while the drawing shows kids in double beds, this need not be the case, so there will be more room for furniture (dressers or whatever) in their rooms. Finally, that step to bedroom 4 will not be odd at all. I've seen it in other homes. It looks clumsy in the drawing but it isn't. What you'll see when you come up the stairs is a bedroom door on a slight diagonal. It's only an odd jagged step if you walk like a robot, in straight lines along the wall, which is what your eye is doing on the drawing but you won't do in real life.

I really don't see an issue with the rooflines. Looks like the angles are fairly similar and the clean lines of both structures should be easy to coordinate, especially in your open, rural setting. Since you've found a stunning deal, I would say, go for it! I definitely would want to find an architect ASAP and by all means, before you pour the slab, make sure you have a plan to coordinate.

Lighting - pendants over the servery bench should be another feature that complements your chosen kitchen surfaces. So whilst I love the copper pendants in picture 1.. They could work depending on the rest of your decor and would be a highlight in a neutral white/timber kitchen = Good! If you choose copper you would complement it with a couple of copper bench top items. These are beautiful! (I collect copper because I love it, my kitchen pendants are silver, I renovated to sell in the next 3-5 years) You will see a picture starting to form in your mind and there is nothing wrong with making a statement with your lighting. I found that when I wasn't sure I would get a very strong sense of what was right and what was wrong for a space, then common sense or passion would determine the outcome! Here are another couple that might work, look her on Houzz under lighting, search pendants, then have fun looking!Timber tones with black or white to complement your cabinets... or Statement white pendants for a bit of quirky fun! Your personality can be reflected in your lighting and accessories creating that point of difference from the predictable white on timber look. Plus don't forget the power of greenery to punctuate the theme!

Without knowing any more info , I'd say its near impossible for anyone but you to know what colour/s to choose -- do you want the house to blend in but have its own style , or do you want it to stand out ? What colours are your main furniture items and even kitchen etc ? For xxample , if keeping the beige walls , how about doing the eves and gutters and garage door in a tangy ( bright , but not glaring ) orange -- this would work with the existing colours and not require a complete repaint . BUT if your kitchen was mainly various shades of , say , green and teal , and your lounge suite and duvet covers were mainly blue hues , that may 'feel' funny , clashing with the exterior ? Of course , blue and beige exterior may not work with the brown aluminium , as youve recognised . Another option ( a bit hard to tell from the pictures ) is that a light grey ( repaint the beige ) with mid-charcoal base boards may work with the brown aluminium , then a bright colour on the gutters and front and rear doors to suit -- anything from sea blue to bright yellow , orange , red , even white or off-white would probably work .