Thanks! you do seem like an expert to me...according to your name as wellThat picture of the bird in the tree is a male western bluebird, and you can attract them to bird feeders with mealworms.
The picture with the two yellow birds are Lesser Goldfinches OR Lawrence's goldfinches. This is an irruption year for them, so you are lucky to see them! The one on the left is a female and the one on the right is a male
The little sparrow like birds are Golden Crowned Sparrows- all pictures are of adults (both genders look the same) .
I'm not an expert, although I am a avid birder.