Miss EmmaH;

You said : Hi everyone! I already had a family ask me for a sibling discount when their new baby comes (they don't want to pay to hold their spot on mat leave for both kids but expect their spot to be held? Is this normal?

I think it is normal that parents ask but it's not always normal they get it. Parents will always ask for the best deal for them but you don't have to give it.
No sibling discount here. All the babies get the same care and love and food so they all pay the same. Sibling discount is for big centers. If they want the benefits of big center then they can go there. If they want a day home then the rate is set and no discount.
If they are not paying for places to be held then they can't make you hold them. You have bills to pay for your own family. If they wants places, they pay. If they don't pay then they have to crossed fingers and see when the time comes.

You said : I have an ECE degree as well as being a certified Montessori educator and 10 years of experience being a nanny.
Do you mean babysitter? How can you be 24 and have 10 years being nanny. That means you 14 when started? And you also got degree. Doesn't make sense. Maybe you 34?

You said : Another thing I have issues with are prolonged pick-ups and drops offs!!!!! Dear lord some of these parents could talk for hours and its so inconsiderate, considering I have other children who are waiting for my care. One mom came for pick-up and played with her child while I was holding her for about 30 mins with a lanyard??????? Really??? I tried to get out of it by saying there is a baby crying for me and I need to go attend to her needs (there really was a baby crying) . Her reply was " Its okay you can go get her we will be fine" I assumed her was going to see herself out. I didn't hear the door shut so I walk out and shes still standing in my hallway .....like why are you still in my home GOODBYE!....I don't want to be rude but what can I say to get out of the conversations? I don't have time for that I have other children and parents waiting for me and I think that's so rude!
Be firm. When they come, start taking coat off child and then say Bye and turn to go work. If they make to follow ask them if they needed something. Tell them you are busy and can't chat socially but if they need to tell you about their kid then they can.

You said :Lastly, what do you all charge for late fees?
$5 for every full or part 5 mins. In the contract. You can't just apply late fees if not in contract. If you have a service provider like cable, power, cell phone, whatever, and they charge you late fees that were not in contact then you would not pay late fee. Same thing