Theoretically yes, just pretzels. But there have been experiments with full sandwich catering on the 1840 recently so you may be in luck (...) Ask nicely at check-in if the flight is full; your supervisor, according to the rota, is Cynthia Cruickshank. She takes no nonsense, but on the other hand she'll know if there are any op-ups to be had. She's got a tight, grey, bob haircut; aim for her at check-in. You're brave surrendering your vouchers - I'd have waited until a transatlantic or a MAN or LIN or summat. Still, good luck to you. What fare class are you in?
As for for the strange thingies at EDI, I'm told by the BAA press office that they are there to provide drainage information to those planning the taxiway extensions (and new rail link, presumably...). Aside from that, I'm in the dark. I will confess that the current work on gates 9, 10 and 11 threw me the other day. I sleepwalked out of the lounge at 0620, joined the usual queue directly opposite at Gate 6, got to the front and was then politely informed that Gate 6 was in fact the Flybe departure for Southampton. I blushed suitably.