You could check google map. From Lagoon Tower, Rainbow Tower gets in the way.
My understanding is that even OF room is not perfect to see fireworks.
The following thread would give you some extra information about the DH side rooms.
https://tugbbs.com/forums/index.php?threads/lagoon-tower-ocean-front.226980/
Lagoon Tower is not squarely facing the east, rather south-east. So to see the sunrise,
the beach is a better place. If you have not done DH, the sunrise from the top is gorgeous.
For 7,000pt GV 2BR, you should ask a higher floor. The album shows view from #1072.
https://goo.gl/photos/ECfGx3pPvwEmM7Ne7 Category-wise, it's GV but is actually OV.
If you are assigned to a lower floor, you will face the parking. February this year,
I had a reservation of this GV unit for my son. He made the request and did not take
the room immediately available at check-in. My advice worked well for him.
Hope you will enjoy your stay.