Hi Folks!
I saw the entry of the japanese Team. I would swear i heard
the theme of Nemesis 3!! 
Olympic Games! Nemesis 3
You are right 
The weapon selection theme? (however, for other systems it's from Gradius II looking at some tweets on twitter).
The Olympic Games opening parade playlist:
- Dragon Quest “Overture: Roto’s Theme”
- Final Fantasy “Victory Fanfare”
- Tales of series “Sorey’s Theme - The Shepherd”
- Monster Hunter series “Proof of a Hero”
- Kingdom Hearts “Olympus Coliseum”
- Chrono Trigger “Frog’s Theme”
- Ace Combat “First Flight”
- Tales of series “Pomp and Majesty”
- Monster Hunter “Wind of Departure”
- Chrono Trigger “Robo’s Theme”
- Sonic the Hedgehog “Star Light Zone”
- Pro Evolution Soccer “eFootball Walk-on Theme”
- Final Fantasy “Main Theme”
- Phantasy Star Universe “Guardians”
- Kingdom Hearts “Hero’s Fanfare”
- Gradius “01 Act I-1”
- Nier “Song of the Ancients”
- SaGa series “The Minstrel’s Refrain: SaGa Series Medley 2016”
- Soulcalibur “The Brave New Stage of History”
Fantastic 
.