Hi, my husband and I are American citizens living in Barcelona. Like you, we and our 3 children moved here because my husband’s job transferred us. It is not true that you have to wait a year until you can join him. Your husbands company in Spain needs to apply for approval from the Spanish government to hire a non-EU worker. Once they get that permission, you and your husband and any children can start the process at the same time to apply for residency permits. His will take less time than yours but there is no waiting period - just processing time which varies. Depending on how well organized your husband’s company in Spain is and how familiar they are with this process (my husband works for a Fortune 500 company and they are horrible at details like this) plus the pace for these things at any given time in Spain (don’t even try to get anything done in August here, no one’s around), the process can take 2 or 3 months to a year. From the time of my husband’s official job offer to the issuance of our permits was 7 months for my husband and 9 months for me and the kids.
However, we moved to Barcelona when the permit process was just barely beginning and my husband started work before having his work permit. By the time our 3 month tourist visa period was over, we were still not even close to getting our permits. Technically this was illegal but the reality is that there are no problems going in and out of Spain and living and working here while the process is ongoing. We were very worried about the glacial pace of getting stuff done here but countless other expats here told us the same thing - don’t worry, everything in Spain takes time, people come and live here all the time without the permit process being completed and nothing ever happens. The best advice I received was from our relocation agent here in Barcelona. She told me the first time I talked to her not to worry about the permits, it will take longer than you want it to, it will be a confusing process and you will probably spend time here without them but it will be fine. It took me a while not to worry about it but everything she (and other expats) told me was true. Just come when your husband comes and let it happen as it happens.
By the way, if you have school aged kids and want info on the international school choices in Barcelona, I’ve got a lot of advice on that topic too.