Chibiusa also does this in similar way to pegasus the old anime with the Crystal Carillon she uses the Twinkle Yell method. Why is that?

Well, for moon spiral heart attack in the manga, she only did it once-probably to help get used to the new attack. No idea why they made it every single time for crystal, since she was able to use it normally in the rest of the arc in the manga. 

As for Chibi Moon, the entire attack is outsourced to Helios-so she needs to call him in order to get it to work. I think. I never did figure out the Twinkle yell attack lol.

The Spiral Moon rod is "technically" given to Sailor Moon by Neo Queen Serenity in the manga and therefore in SMC. The 90's anime had the rod form out of Serenity and Endymion's love for one another, so it negated that bit.

Chibi Moon's Twinkle Yell is a little bit harder to pin down. In the 90's anime the Crystal Carillon basically replaced the Pink Moon Stick as it could also shoot out pink hearts. It's use to call Pegasus is due to the manga, where Pegasus gives Chibi Moon the Carillon so she could call to him. In the 90's anime both Sailor Moon and Chibi Moon had to rely on Pegasus for their weapon, whereas in the manga Pegasus/Helios only helped guide the Moon Kaleidoscopes to the two girls, and the weapons were powered up with the girls' own power. I'm not sure why Toei changed it for the 90's anime, but it might be to give Pegasus a reason to appear in every episode and keep his character relevant and present within the plot. In the manga things happened a lot quicker, and Pegasus/Helios' role quickly switched from someone providing power/assistance to someone providing information. The pace of the plot is a lot slower in the 90's anime, so the animators needed to change up Pegasus' role or else the story would advance too quickly.