Gruezi Floaty!
Firstly I must apologise about not getting back to you with tips for the interview - but you obviously didn't need help anyway...CONGRATULATIONS!
I was interested to read of your experience with LX. A friend of mine in SYD received his offer in the same fashion. He has an EU passport, speaks the language of that country but has hardly any knowledge of German. He's learning and very keen mind you, but it's not conversational. I speak German and can hold a conversation beyond simple textbook stuff, but still cannot understand TV, radio or the newspaper properly. I would doubt my ability to gain a position with LX based on this, so I have been wondering how my friend got the job. You on the other hand should not have to speak German if you have French and Italian - the website stated either French/German but if you want a ZRH base I suppose you will have to improve your German. It sounds like you have a knack for languages so I'm sure you won't find it too hard. Are there any openings for GVA or LUG bases? At the end of the day though the official onboard and company language is English (you'll be pressed to find any FA manual in German, trust me!).
I just flew SWISS home this week and got chatting to the purser. He said that one should wait till about May before accepting a position as the company is still in a shaky phase. My partner has just started with the airline and he says the same - he cannot understand why they still interview if they plan to fire.
With regards to this letter just accept it as the company's intention to hire you. My partner hadn't even received a contract with his start date - which means that he could have turned up and the company say that he wasn't needed. As a Swiss himself he admitted this was an unfair and inconsiderate practise. My Australian friend has the same condition attached to his offer - that he improve his German.
I'd love to work for them as they have a real network etc (don't get me going about Qantas at the moment...) but if you're keen on learning German, Switzerland is not the place. Dialect is not even similar to Hochdeutsch and you won't get much practise in onboard either. That's the only thing holding me back from applying. Floaty, whatever you decide I wish you luck. My advice is just to be very careful with SWISS - I'm sure they have the right intentions as a great airline, but staff numbers will be affected by how well they get themselves out of their financial mess (remember that the new SWISS was funded entirely by taxpayers and that's a sore point for the Swiss at present as I'm sure you'd know).
Let us know...tschüs!!!