Romani stared and blinked a few times before asking "What's the favor?" "Those temples you went to with Blue, I need them to be closed and impossible to enter. There's a lot of dangerous monsters in there and I want everyone to be safe." Majora said.

I was filling the Boss Chambers of the 4 temples with the Excessive ammounts of Powder Kegs I bought

(That sounds like that'll will destroy Termina along with Hyrule. 0_0)
"I guess so." Romani said. "Great, you are such amazing help. As an early thank you present I will you give a magical voice." Majora said, casting another small spell of darkness on Romani. "You can now sing songs of magical properties." Majora said. "Try this one." Majora said, teaching Romani the Song of Soaring.

(It's only 6000 per chamber. XD)
I was debating if I should detinate the Powder kegs now, or later.

(That's still 24,000 powder kegs.)
Romani sung the Song of Soaring, arriving at Snowhead Temple.

(Wait, is Majora still the villain here? or has he actually turned over a new leaf?)
I was still pondering when I should detonate all 24k Powder kegs

(I haven't totally decided yet, but I'm definitely leading to one side than the other. You'll see very soon what path Majora will take.)
Romani gathered water and placed it in the entrance and watched as it froze as soon as it touch the ground. After a while there was an impenetrable wall of ice, blocking off all access to Snowhead Temple.

(But Blue would just blow it up anyways. XD)
I was still thinking about blowing up all 4 temples

(You could blow up pretty much with 24,000 powder kegs.)
Romani sung the Song of Soaring and traveled to Woodfall temple.

I decided to keep the bombs there for later, Until it was needed.

Romani poured a growing elixir that Majora must have given her without her remembering. Almost instantly vines and roots grew all over the exterior of the temple, so thick that it almost doubled the diameter of the temple.

(I don't think it'll hold when Blue does his experiment. XD)
I went to the Great Bay temple for a bit and stared at its well-made mechanics

(Can anything withstand 24,000 powder kegs?)
Romani sung the Song of Soaring and traveled to Stone Tower Temple.

(I think 24k Powder kegs have the strength of about 4 Nukes XD)
I was still in the Great Bay temple

(Around there probably.)
Romani started to roll stones in front of the temple entrance.