Haven't read rest of the thread but just wanted to present my views on soya.
I've used soya for years but when I'm pregnant or bfing I avoid it as much as possible - from certain sources. I've also discussed this with a dietitian, who agreed with me.
Soya contains high levels of phytoestrogens, which, in the body, mock human oestrogens and upset the hormonal balance. (This, btw, can be redressed by increasing your intake of lentils, mung beans and dark green leafy veg - all of which help your body to clear out the extra hormones)
Eastern soya products (tofu, miso, etc) are fine - they are fermented for months and so the phytoestrogens are removed by this long fermentation process. Western soya products (milk, cream, soya mince, etc) are only fermented for a short time and so the phytoestrogens remain in high volume.
Soya is present in a huge range of foods - it's estimated that up to 70% of what we consume contains soya - check the labels of cakes, biscuits, just about anything. 'Textured vegetable protein' is one of the terms used to describe it on ingredient lists. Soya flour is another form. It's cheap and good for bulking out food mixes. It's also present in much animal feed - so when we eat non-organic meat (and possibly organic meat?) we are eating yet more non-fermented soya.
My theory is that the rise of unexplained infertility in this country could be explained by the high levels of soya oestrogens we're unwittingly ingesting. This can then get passed to the baby through breastmilk/ in utero. And could, IMO, affect their fertility.
You can increase your calcium by eating foods such as tofu (well-fermented!), tinned sardines (with skin and bones intact), fortified oat milk, almonds/ almond milk, nuts and seeds, whole grains and fortified cereals. Do ask for a referral to a dietitian and they'll be able to help - calcium intake is essential for women, especially breastfeeding women, because of the risk of osteoporosis. As the bf mother of a dairy-free baby you may need special support.