Without the "kid," if you're after a real taphouse experience, and you're staying downtown, go to Max's (Fells Point).
For tours, see ^
Heavy Seas is great, but it's not downtown. It's in Halethorpe, on the West side, off the Beltway. And AFAIK you've got to register in advance for a tour, unless you know somebody there.
Union sounds great, but I'm not familiar with the brewery, only their beer
.
There are other breweries within driving distance. Jailbreak in Laurel is a fairly new one and their approach is a bit novel. Flying Dog in Frederick is the a one, and there are 1 or 2 others in that town, Monocacy being another. Hard to keep track.
You need to check ahead for kid friendliness for visiting the breweries and those tours. For example, the breweries' taprooms don't even have soda... Maryland is also pretty darn strict with crazy laws, we're drowning in them. Check their websites and call before you even leave home.
Hope you find something that's amicable. Enjoy your stay, I mean it, there's a lot to do here.