I have one of those electric frothers but one that’s branded for matcha lol but I only use it for milk, it seems to have a more powerful motor. With the right technique I can froth some microwaved milk well enough to get some latte art, but it’s tricky and would be really easy to make a mess for a kid.
There’s a new product from the company subminimal called the nanofoamer pro and YouTubers seem to agree it’s the easiest and best hands off method for silky milk, it heats and froths for you. But it’s kinda pricey and you’d have to teach the kiddos to clean it immediately after using it or milk can kinda scald to the inside of it. It might be worth looking into.