In my opinion “good with children” has a lot more to do with the individual chickens and how they are tamed or managed than it does with specific breed. Still, you might go through Henderson’s Breed Chart to see what traits the breeds are supposed to normally have. If you look them up on Feathersite you can see pictures. That way you will have done your due diligence. I’d look for “takes confinement well” and “not flighty” among other traits.
Henderson’s Breed Chart
http://www.sagehenfarmlodi.com/chooks/chooks.html
Feathersite
http://www.feathersite.com/Poultry/BRKPoultryPage.html#Chickens
Are you happy with your Silkies? Why not just get more, maybe different colors? A lot of people have Silkies in their flocks that also contain full sized dual purpose breeds and don’t have problems. Some people say their other birds pick on their Silkies. I think a lot of that comes from how much room they have and the personality of the individual birds, but it does seem to be reported more often than some other combinations.
Another issue is that Silkies cannot fly. You have to set up your coop with that in mind. You may need to modify your coop if you mix Silkies with birds that can fly.
My next thought would go toward other decorative breeds like Polish or Cochin, especially bantam Cochin if you are OK with the egg size. These decorative breeds tend to go broody a lot, like Silkies, but they have been bred to be pets, not production breeds.
Are you planning on hatching any eggs? I’m extremely happy with my mixes but my goals are different from yours. If you plan to give away or sell any chicks, it might be easier if they are pure Silkie. But it’s your goals, set-up, and management techniques that count, not mine. Good luck on your decision.