My baby girl gave birth to 2 kittens Thursday night, another one on Friday night and two more Monday evening. This is the first cat I've had that took 4 days to deliver her babies. Typically, they are done within 24 hours . Gracie was an exception to the rule and I've had cats for over 20 years. Don't know if this helps you much. But, thought I'd share it with you.
My cat had babies 1 week ago and her mucus plug went at 12pm and her first kitten was born at 2.20pm the rest were born within 30 mins of each other I have never witnessed a cat giving birth but my cat did really well and now she is the proud mummy to 4 babies but they make really strange noises during labour and just be care full they don't go outside-as my cat was looking for somewhere dark to go during the morning so make sure you have a big box ready that is cosy for her good luck ...