I can confirm that during your probation year some crew controllers will put pressure on you accepting the last minute back to back upon arrival in LUX or working on your days off.
Commuting is possible, but not always easy by air travel depending on where you live. I would not recommend it. Everything within driving distance is fine.
Roster during your first 2 years is pretty horrific. Do not believe the roster they show you during the assessment. Expect to be used to whatever is legal, especially during peak season. I highly recommend to divide your leave over the 13 rosters as it makes it more bearable. Expect very little roster stability and MASSIVE delays. You can only plan your block of 6 off days. And during your probation year they might pressure you into working these as well. You can say no! No questions asked. And if you choose the 2 for 1they will probably not call you again. When you get your first RBO it gets a little better.
Just to putt it into something easier to visualize: you will do roughly 2 rosters more productivity on the B-scale compared to the A-scale. 26 RBO’s and some leave days.
I personally would not have joined in hindsight. But that is easy to say. Good things; great network but unfortunately very short layovers usually. Great colleagues and good training. Also the tax and social system is quite good in LUX.