I can only comment about the cowhide rug idea as that's my area of expertise. Cowhide are still going very strong as a design trend, they haven't been overdone in my opinion. Also cowhide rugs break all the normal rules of standard rugs because they are an organic shape. So they visually take up more room than they physically occupy. So you don't need a cowhide rug to be as large as a wool rug. They also look better on a 45 degree angle to furniture and it is OK for one or several legs to go underneath furniture as this can anchor a group of furniture. For how to clean a cowhide rug there is some great info on my website plus a video that is really interesting.

Can anyone tell me what the actual difference is between a "living" room and a "family" room? Also is a "lounge" room just another name for either one of the above? Thanks

I agree with Jabinika that it doesn't look great just now. However if storage is an issue its a wasted space, and should be put to work. It looks as though many things are not yet finished. With lots of light paintwork and some aesthetically pleasing storage boxes, I feel it will do well. It would be good to see a pic of it complete.

There are indeed building code safety requirements that govern the design of balustrades, including the gaps around panels. Sometimes compliant gaps at the maximum opening look a bit off. I find that smaller gaps, 20 - 50 mm often look more pleasing. You say your patio is not covered. In that case there is little potential for any balustrade to trap heat. An uncovered north facing tiled patio will be a heat sink, and a glass (or substantially open) balustrade will allow more sunlight onto the tiles which will increase heat gain. A solid balustrade may reduce that heat gain due to it's shading potential, but I am guessing you want glass for the view, so if heat is a problem, consider adding a roof covering to shade the patio.