DSH, Domestic Short Hair? or DMH, Domestic Medium Hair?
Willow is a diluted blue/cream tortoiseshell.
Tortoiseshell cats have a sort of "brindled" appearance, with their black and orange (blue & cream) colored hairs intermixed in a loose and jumbled pattern. Your cat is a black/orange calico cat with the tortoiseshell pattern (no agouti). The dilute gene turns the black/orange to blue/cream. A cute shortening of the name tortoiseshell is "Tortie".
A "Torbie" is a tortoiseshell that has agouti. Agouti is the gene that causes the striped tabby patterns to appear on black/blue cats; classic, mackerel (striped & spotted) and abyssinian. Tortoiseshell + Tabby = Torbie. All orange cats (and all calico cats with orange) express a tabby pattern, even if they do not carry agouti to make the pattern appear in their black/gray fur.
Calico describes a cat, usually with a lot of white and/or distinct patches of white, black and orange fur.
She ... does this bird-like chirp/meow when I call her name...
Is it like a "mirp! mirp!" or does it sound like a "trill"? A trill is sort of a cross between a meow and a purr done through closed lips. My Toby would sound like this: merrrrreeerrrrerereeeerrrrrrrrip!