(might be) Moving to Barcelona from Czech Republic with 3 small kids

Hello,

I don't know, if I'm creating the right thread. I have many questions, but most of them are about kids.

I'm living with my family in Prague, Czech Republic. My husband got an job offer in Barcelona and we would love to move there at least for few or many years or forever who knows. 

Everything is just very complicated, because we have 3 small kids. They are 1, 3 and 6 years old. The middle one is now in kindergarten and the oldest just finished and in September 2018 will start primary school. The relocation should be probably in Autumn. We now realized, that there are not primary schools in Spanish, but only in Catalunyan, is that really true? Well I'm speaking with my kids Czech, me and my husband are speaking English and my husband has mother language Spanish. We thought to put kids to put to schools with "classic" Spanish and that's my question - is that possible? Another question is - how expensive are Public schools / kindergarten and how expensive are Privat schools / kindergarten?

Another question is - as we are 5 member family, we would be looking for apartment with 3 bedrooms, living room+kitchen. My husband's job would be in the center of Barcelona. I love city, I'm not so much a village person, but I read, that lot of people like to live with kids more far from the center, I don't know, where to start about concrete research. I think, that for some time we are not going to have there a car, so we could be using train, if we wouldn't live in the city. Are the prices of apartments really that different in/out of the city? Please, if you can, write me some concrete opinions, tips, prices, that I can easily consider everything. My husband's job are quite in hurry in starting to work there, so everything is quite fast for us and I don't have so much time to sit at the computer and search, read etc.

I have million other questions, but I will write them later, if I see, that this forum is really active

Thanks to everyone in advance and have a nice sunny day.