You mean the Larsen Family, don't you?!
Lauren Larsen can be invited to step family house, manualy (today, or tomorrow), or automatic (randomly). She will appear at 21:00 at step fam house. After a few times (or maby one time was enough...) Bridgette also comes over with Lauren. And after 2-3 times doing this routine, Alexa will appear in your class...
Maybe you meant another event, but if you meant the new one from v0.40, then it's the Larsen's.
Family (Gardners #1) joining step family (Gardners #2) was looong ago, and this doesn't trigger Alexa to join your class...
But thank's for your guide, help me a lot to avoid the grind, cya
