Squab isn't "kinda like pigeon", it's pigeon, baby pigeon.
Squab is a pigeon under 4 weeks old.
Hetty starts running into doors as she tries to pass through them as she is getting used to being solid again. However, at the beginning, when she hasn't realized she's in Jay's body yet, she somehow knows to open the front door to approach and insult the Irish exterminator.