The first thing I would say (apart from congratulations, I'm glad you're feeling happy with everything so far etc.) is avoid American Catholic online forums and social media people like the plague, at least until you are very well settled into your Catholic community in real life. The American Catholic Church is, like their politics, very sharply divided along identity lines between liberal and conservatives. It can be a toxic environment, it's very hard to understand unless you know the background situation, and it's a very different setup from the average English Catholic experience. A fair number of new Catholics every year get dragged into an exteme version of Catholic integrationalism/sedevacantism/various conspiracy theories from social media interactions with some of these people. This is not mainstream Catholicism, and far removed from the mainstream English Church in particular.
There are respected speakers online from the US, such as the people from Ascension Press, the Augustine Institute, the Aquinas Institute and so on. But steer well clear of the instagrammers, just as you (presumably) would from their secular counterparts such as the trad wife community.
After that, time to consider family size. First of all, it is a discernment between each couple and nobody else's business, unless you choose to seek advice. Each couple has to consider factors such as finances, emotional resources, care of existing children, state of the marriage, and so on. Basically, the things that everyone should be doing anyway when they plan a family are explicitly imposed on Catholics as their duty. There is no obligation to have a large number of children. There is, as you say, an obligation to avoid artificial contraception, but NFP is an excellent way to regulate pregnancies for most women (and if there are health concerns that mean it would be dangerous to the woman's health to get pregnant, there are moral theologians and Catholic doctors who can advise). There's also a feeling that we should avoid what is called a 'contraceptive mentality', which more or less boils down to the idea that you would welcome another child if it came along, planned or not, and that you never say never to the idea of having more children even if, in practical terms, it's very unlikely that you would be in a position to plan another pregnancy.
In terms of your toddler, it depends how far you're willing to travel for a Sunday Mass and what's available in your area. Parishes vary a lot. There are plenty of Catholic parishes who have what you describe in the CofE parish, but clearly not the one you've already been attending. It's considered absolutely fine to church shop a bit within the Catholic denomination to find a parish that suits your needs, and also fine to attend one Mass with your family and attend RCIA at a different one. You will find that the different Masses within each parish may be more or less set up to entertain young children, although they should be welcomed at any Mass. You will only usually get children's liturgy, for example, at one Mass each week. On one level, it's very nice, especially as a new Catholic, to have a home community where you feel welcome and valued, but there's nothing wrong with trying out a few local parishes and going to different ones each week.