I'm a sucker for the neatness of the square.

My dear departed mother was never much of a drinker but every Christmas morning the two of us would have some form of champagne cocktail. Often a Mimosa, which went down a treat. BUT the year we tried a champagne and strawberry liqueur mix was a disaster. Well not for mum and I, we giggled through until mid afternoon when crashed for a nap. When we woke we realised the peas went unserved, some people had the wrong presents and there was something very charred in the oven. The family still talks about the year we were too tipsy to cook lunch. This year it'll be straight champagne (and after 8 years I still miss her dreadfully).

Yours do look very nice but don't forget there are 1000s of homes with laminate bench tops with cook tops sitting directly on them. Don't think that the sides of a BBQ get hotter than a wok burner. I do like your first pic, the more compact one. What would be the approx cost sans BBQ?

A lot of the time they build a core filled concrete block wall then construct another stone wall against it. The concrete block wall takes the job of retaining while the stone is for looks only. It does depend on what purpose the wall is performing. For example a retaining wall higher than 600mm (usually) needs engineering by a structural engineer which is easier to achieve with core filled concrete block on footings rather than just solid stone. You never mentioned the purpose of the wall which is a vital detail as there can be numerous ways to achieve similar outcomes.