My infant daughter is accompanying me to the US on a J visa, from the UK. Will I be allowed to bring her with me to the Visa interview? Or will I need to arrange child-care?
I'd bring her along, especially if she is also applying. We unfortunately found that many US consulates behave quite inconsistently. We had multiple occasions where the information provided during the appointment process: "no problem, your kids do not need to be here" turned out to be irrelevant during the actual visit "no, I can't do this, because your kids are not here".
In one case we actually got a written appointment confirmation that explicitly stated that the kids did not need to be physically present. However, the confirmation letter arrived two weeks after the actual appointment, so it didn't help.
It's unclear whether the consulate have any set of rules or guidelines for kid's being present, but even if they do, they often won't follow them or just make it up on the fly, and there is nothing you can do about it.
Your best bet is to be as prepared as possible: bring all family members and any conceivable documention (birth certificates, driver's licence, a few utility bills, letters/communication with the school, attorney, etc.)