Here you go, strong steel supports. https://www.google.com.au/search?q=Large+workbench+brackets+for+kitchen+island&ie=UTF-8&oe=UTF-8&hl=en&client=safari#hl=en&q=invisable+steel+bracket+supports+for+kitchen+island+in+Australia

You're lucky to have those tracks, they would of been custom made. Depends on your budget really. If not much- cut down what you have and hem them. If more $$- I'd speak to a curtain maker. Remove the pelmet and have a 2nd track attached to the one you have for a sheer curtain (to hide/soften your bars but keep the view and light). I'd then use the existing track to get some nice block-out curtains made to close of a night. With well made pinch-pleat curtains you won't need the pelmet.

personally, this is an area that depending upon your budget is arguably something where you can consolidate on and it won't dramatically be a deal breaker either way. Slick/contemporary is always going to look good in the right space, but similarly a simple less "flashy" option will just sit there somewhat understated. I like even just the plain white to blend into the walls more than stand out. Usually i leave black plates only if mounted on timber. At the end of the day a switch is a switch, is a functional element and with the product you're predominantly paying for the look one way or the other. I'd probably lean on higher quality of understated style rather than say a trendier option at a lower price point. I think it depends upon the project and the general level & style of finish/fitout. These are ultimately personal decisions but I always advise to think about consistency and settle on the option that best balances with your budget and the general design - good luck :) PD

Search around for corner curtains rails. This will mean installation of a new, complete rail that goes around the corner. IKEA have curtain rails that go around corners. If your friend would like the curtains to pull away from the corner, then install normal curtain rod/rails higher above the window frame and just below the cornice. Then they can be positioned individually without having the window architrave in the way. And curtains can be pulled away from corner.