My 3 year old has to repeatedly say good night in 5 different ways at night in a specific order and tone or she has a severe tantrum?

Rituals: Children at this age like rituals. They want to do things the same way because it gives them a sense of security. At the same time, this may be a delaying mechanism to avoid going to bed. Get her ready for bed a bit earlier, and give her a time limit to say her goodnights before putting her in bed. If she has a tantrum, try to ignore it and be consistent about the bedtime.

Yes, night-time : rituals are common in typically-developing tots & you extinguish stalling by consistently ignoring it. Expect protests before it stops. Read, cuddle, brush her teeth & put her in her own bed for sleep onset. If you are concerned about her insistence on a ritual's being a sign of an Autistic Spectrum Disorder, complete the screening tests on firstsigns.org & discuss results with pediatrician.