You can actually get the full chart for the three songs from easy to master/remaster.
You need to go to Sinmai_Data > Streaming Assets > A000 > music
Just copy all the files there from the SDGB (舞萌DX) and paste them into the same directory for SDEZ.
Then at A000, copy all SoundData and paste into the same directory.
Then also at A000, copy all MovieData into the same directory.
DO NOT REPLACE ANYTHING FOR ALL OF THEM, when the prompt comes out just skip.
Then, you need to go to the Music folder, open MusicSort.xml
Add in the following line
<StringID>
<id>11568</id>
<str>INTERNET OVERDOSE</str>
</StringID>
<StringID>
<id>11566</id>
<str>Knight Rider</str>
</StringID>
<StringID>
<id>11565</id>
<str>Let you DIVE!E</str>
</StringID>
Add in under <SortList> like this
The songs should appear like this.
If it still does not appear try going to mai2.ini
Set AllOpen=1.
It worked for me.
Hope it helps!
Oh yeah, I wasn't able to locate where the song icons/pictures were located inside Sinmai_Data. Therefore the icons for the new songs is empty. If anyone knows please share, thank you.