RE: Brother-Sister Halloween costumes
How about cowboy and cowgirl? With a little one year old it could be very cute with a little hat and boots! My brother (who is four years younger than me), and I were always being dressed as "combos" for Halloween by my mother. This is one that has the best pictures in our album. I wore a fringed skirt, suede vest, hat, boots, etc. He wore (at age two) jeans, mini-cowboy boots, hat, vest with silver sherrifs badge, and holster with gun (not very PC today though!)--you could do a rope laso instead.
We were also Wonder Woman and Batman, a cheerleader and football player, clowns, and my mind is drawing a blank on the others. Good Luck!
Mama to "The Fantastic Four":
DS 02
DD 06
DS 09
DD 12