Hi again op. Ok, Torrevieja is TOTALLY ex pat I mean HUGE! You won't have the regional Spanish issues in school though which is great. Children will go to a local school fine. Most will probably be a certain type of British though. I don't think it's what you are after, as a young family. Fine to visit, not to live.
However, I don't mean to sound horrid, it is not a nice area and is known as torrerobbery or something, all the thieves in Spain reside there (according to local gossip) you won't want to stay there long, so DO rent.
I would highly recommend Denia to you. It is further along the coast but not much, still Castellano, quite a few lovely Germans, English too, but much more upmarket and cosmopolitan with good local school, a very good private International school too. Property is much more expensive than Denia though, with good reason.
It also has a regular ferry to Ibiza etc. It's beautiful, lovely coast.
As you speak French, this is good, most Spanish speak French. I spoke French for my first few years here.
For the NIE I know you have to prove you have 15,000 euros in the bank and regular employment if you are not Spanish/married to a Spaniard, it all gets easier after that. That is the biggie. Before you get that you have to be empadrinando at the local town hall, proving you have a rented address where you reside. That is relatively easy. You will need an electricity bill or similar and your rental agreement and passports etc. Getting an electricity bill is going to be tricky without the NIE but you can do it! It's a crazy catch 22.
You have to reach into the depths of your inner patience at all times, unfortunately, you are going to have to hire a 'rip off Britain' translator' (will be loads in Torrevieja) to start with. Negotiate EVERYTHING! They are usually 20 euros an hour.
I believe your husband, if bringing English money monthly, into Spain (you'll have to prove this), will be largely exempt from paying tax until he hits 20,000, then he will, you'll get healthcare eventually. But, be prepared for that battle, as it is a battle.
Spain right now, as opposed to when I moved her 15 years ago, is very suspicious and totally cracking down on health tourism and families moving here from abroad, taking up resources.
Lastly, buy an apartment, not a house with garden, (eventually after you RENT first) Secure and safe and the way it is out here.
Not going to tell you about my robberies when I first got here. Live in a flat now!