Semi-chronological order of the 911 an spin off series to binge watching one serie at a time and switch only when it makes sense
911LS s01e09 - minor reference to one of the parent serie's events
911LS s02e02 | 911 s04e03 -> 911LS s02e03 - ends of the second episode of LS season two and third episode of the parent series season four conclude in a crossover in LS third episode of the second season
911LS s03e11 - familiar face from 911 pops up