First - congratulations Elinoee!!!
Second - I have never hit the limit for played sims before. It hasn't been an issue.
Third - along the way, I found a 38th milestone - would not be shocked were there more.
Fourth - I, too, made a list of all potential mothers in alphabetical order, starting with Alice Martin and ending with Zoe Patel and noted their ages. A list of all empty houses in order of cost. For families with more than one potential mom, I split the moms apart before playing.* For most moms, infant adoption.
The Spencer-Kim-Lewis household has:
A - a bunch of money (for things like all the fancy infant stuff, maids, butlers, etc)
B - 4 non-working adults to for round-the-clock child care and milestone help (and a child who can also do some of those things while being otherwise neglected by those 4 non-working adults)
C - a lot with bad sightlines
So, Alice started 3 kids on day 1- (adoption, science, and pregnancy). Almost all the focus was on the adopted child who hit most of the milestones while waiting for the other two to be born & age up. Meanwhile, Denis and Eric started working their way through the A & YA women alphabetically. (They only got to the M's. Olivia has a lot of new, young relatives). Because Alice's pregnancy was first, that baby was the "timer." Once it aged into an infant, the pattern was change houses, adopt, then (if needed) do additional milestones, then wait for the newborn to age into an infant, then move on.**
Could not get a kid to blow a kiss or play peek-a-boo. I had to stop early (again. I need to time these better), so Zoe's kids could have made it, but...
I also got this lovely picture:
[ You are not allowed to view attachments ]
* a couple of exceptions, e.g., because of neighborhood stories, I couldn't find a families. The Free Spirits do not have any money and could not afford a second house, etc.
** as it would change the score, I do know how many babies were adopt only v. the ones I made happen while playing the father.