Try a new posting, probably in the Where am I, Where are you section, offering to split an order with someone in your area. You may get lucky. Or post in the buy, sell, trade section you are looking for pullets in the area. You can also try Craig's List.
Almost any chicken can handle the heat if you give them shade and they always have access to clean water. As far as breeds, silkies may be a good choice but they go broody a lot. I consider that a good thing about them, but having any broody around a young child may not be good, plus you need to break them from being broody. That may negate your requirement for low maintenance.
I'd recommend the Sussex, Orpington, or Australorp as the full-sized breeds to consider, considering your quiet and friendly considerations. The Orpington's do have a reputation as being a broody breed, similar to silkies. I know Gritsar loves her mellow Brahmas which apparently are not broody, darn her luck. You can look at breeds and get a general idea of their characteristics, but a lot of the hen's personality is individual. Rhode Island Reds have a reputation of being an aggressive, not friendly breed, but you will find people on this site who love their mellow, friendly RIR's. I think it may be strain dependent as well as how they are raised.
Good luck.