Hey there Dalena,
Welcome to planDisney and thanks so much for this question! I'm thrilled to hear your trip to the Disneyland Resort is coming up in just a few short weeks.
I'm a huge fan of the nighttime spectaculars offered at both parks, so I can totally understand that you'd want to try to catch them during your trip. On March 7, Disneyland Park is closing a bit early (at 8:00 PM as you mentioned) for the
Disneyland After Dark: Disney Channel Nite. Though, it doesn't look like you'll be missing out on any fireworks that night! Typically, you'll find firework shows on the weekends and projection shows on weeknights.
When there is a special event that closes one park down a bit earlier than normal, but you'd still like to get some more park time, my recommendation is to purchase the
Park Hopper option for your ticket so you can hop over to the other park! Looking at the
Daily Events Schedule, it looks like Disney California Adventure Park will be open until 9:00 PM that night and has a showing of
World of Color - ONE that you'd be able to see.
If you're visiting for multiple days, then you can plan to catch Mickey's Mix Magic at Disneyland Park on one of the other nights of your visit.
Thanks again for your question, Dalena! I hope you make some new special memories on your visit to the Happiest Place on Earth.
Have a Magical Day,
Greg