I tried doing this, but I had a few bugs like my sims not responding or feeding the tots, so I had to use MotiveCheats a few times and hire a Nanny.
If it wasn't for the bugginess, it wasn't too bad, as long as the tots had their Potty Training and Thinking skills up (so they can go potty by themselves and supposedly don't have nightmares as much).
I used money cheats for the beginning to get toddler items, but I am not a stickler about following strict challenge rules. I am just casually challenging myself for fun. :smile:
(Besides, I had bugs which made it impossible, so I had to cheat anyway.)
ETA: I recently have deleted a tot because I wanted a husband for my sim in this household, so it's a six toddler challenge now, lol.
I plan to do another seven tot challenge in the future.