Enrolling 5 1/2 yr old non-English speaker in a school

Hey everybody,

We're a family of four from Austria thinking about moving to Malta.
Our sons are 4 years and 2 months old now, but we won't relocate before summer or more likely winter 2016, so our older one would be around five and a half when we move to Malta.

Of course, our children's education is very important to us, so we are a bit worried how our son will be coping with everything. There are three things that particularly worry me:

1. In Austria, children start school at age 6, so our son won't have been at school in Austria when we plan to go to Malta (assuming that we get there in January 2017), but he would presumably be expected to join in in the first year of primary in Malta (i.e. he will have missed half a year of school). He will go to kindergarten in Austria, but there the kids do not really "learn", they mainly play. Thus, he would not have been introduced to reading, writing etc., and - probably even more difficult for him - at kindergarten there are no "lessons", the kids can more or less do what they want, they do not need to sit down for, like, an hour, so he'd not be used to the somewhat strict setting of a school. My questions now: Given that we'll probably arrive in the middle of the school year, does anyone know if there is the possibility to send him to something like pre-school before actual primary school, even though he is "too old". Or do you think it would not be all that much of a problem for him to catch up with the others?

2. As we are from Austria, my son's native language is German. He does speak quite a bit of English (I'm an ESL teacher, and I often talk to him in English), and he's a quick learner. But of course, he speaks no Maltese. So I'm a bit worried that he might become an outcast, especially because he's quite a shy type around other children.
I've read quite a lot about this issue in the forum and found some very helpful answers, but maybe there are others who have gone through the same experience?

3. As I've seen in this forum, we're not alone with our doubt number three, namely: state school or private school.
We do not intend to send our children to a church school (we're not a very religious family, and I don't have a very high opinion of the Catholic church, but that's not a topic to be discussed here and now...), but I haven't quite figured out if the other private schools (which often have St. in their names...) are Catholic too, or not?! As I said above, our children's education is very important to us, so we want a good school, but private schools, albeit they may be cheaper than elsewhere, are still expensive, particularly when there are lots of other expenses related to relocating, as well... So a state school would be our preferred option. I've read mixed reviews about foreigners in state schools in this forum, though overall, the children seem to be coping quite well. Again, it would be much appreciated if you could share your experience

Sorry about the long post, but this whole school issue is really giving me sleepless nights! Sometimes I wish we'd taken the decision to move earlier, before our older son was at an age to worry about school...