Hazelnut milk is delicious (but harder to find). There's a large variety of milks that I've seen around, I've tried quinoa milk but that thing tastes horrid. Lactose-free milk like others have suggested is also an option. The phytoestrogen in soy shouldn't really affect your body unless you eat lots of soy-based products daily, if it's just a bit of milk in your coffee then I don't think you should worry about it. That said, lots of current nutrition warns against having a lot of soy (again, a bit is totally fine I think) because of the phytoestrogens and I don't know what else. The paleo diet also isn't a soy fan.
Funny thing, when I first found out that soy contained compounds that the body treated like estrogen, I immediately decided I wasn't going to have any more soy ever. And that was before I started thinking I was trans. But I've come to the conclusion that a tiny bit of soy sauce once a month isn't really going to make my body even more feminine, so who cares.