I wasn't sure what to call this challenge as it is a combination of the The "Educate 'Em" Boarding School Challenge and The Orphanage Challenge. The goal is to educate and grow spawned sims from the Tombstone of L&D.

First make some sims to run the orphanage/school.
You can make as many or as little as you like, adults and elders only.
Move them onto a lot and build the school/orphanage.
I built my school with one big classroom for all of them and some party stuff on the second floor.
On the first floor, I built one huge bathroom with toilet stalls and small rooms with showers. I also used the dorm showers, too.
Then I built a big kitchen with seating for about 20 people. Then I built 4 rooms: a room for the toddlers(no babies), a room for the girl kids, a room for the girl kids, an one big room for all the teens. I recommend having 4 cribs/beds in the toddler room and the kids' rooms, and 8 beds in the teens' room.

To create the classroom, you have to go to Simlogical and download the school mods. If you can't then you can run the school/orphanage like the The "Educate 'Em" Boarding School Challenge.
You won't need the school stuff at the beginning, as you will start with toddlers.

To start, open the cheat menu(ctrl+shift+c), and type: boolprop testingcheatsenabled true
Then shift+click on a sim and choose spawn-Tombstone of L&D.
Click on the tombstone that appears and choose spawn/add toddler boy. Do this twice.
Now do it again but this time choose spawn/add toddler girl. Do this twice too.
Now you should have 4 toddlers, you can make more or less, and if you adjust the number, I suggest you also change the number of beds in each room.

When your first group of toddlers ages up, then spawn 4 more toddlers the same way. Continue spawning whenever your toddlers age up. You may have 4+ chilren/teens at times, which is fine because of the extra beds. All toddlers must age up at the same time, and all sims in that group will always age up with the same group.

Rules:
No smartmilk
Career rewards may be used anytime