Now that I traveled through the VIE airport I'm going to answer the questions I posed a few days ago.

1) The shops are after security and passport control.

2) I visited the Longchamp shops in areas F and G. This involved some backtracking to then access the Austrian Business Class lounge, but it wasn't too far to walk.The shops are NOT tax-free, but the clerk said she would do the paperwork to claim the tax back at the windows for that purpose. I didn't end up buying anything, as the prices were the same as in-town stores and the stock was not great.

3) The Longchamp stock in Gates F was small. There was a better selection of items in the store by the G gates, I still didn't purchase anything.

I found the prices in the duty-free stores at the Vienna airport to be high. I didn't buy anything there. I did turn in my tax-rebate paperwork, there were two windows next to each other. My receipts were from Harrods in London and at one window I was told Harrods didn't do the paperwork properly, there was something missing (I don't know what, she was unclear in her explanation.) The guy who stamped my receipts was rude, even though it was early in the morning and there was no one in line. I dropped my paperwork in a clear plastic bin to be processed. I was told I would receive a credit on my card in 2-3 weeks.