This has probably already been long since surmised elsewhere, but I am working through it for my own understanding and because a lot of sources are in Chinese:
Notably, the name isn't listed in JASRAC at all. The Songview entry claims that the reporting participants of the song information are ASCAP, which reports the Publisher information as MCJP INC E GROUP THIRD DIVISION whose PRO (performing rights organization) is JASRAC, and "other non-BMI, non-ASCAP participants", which are the the other two names listed.
In NEXT COLOR PLANET's case, it is Sakai Takuya and Suisei's supposed name totalling the other 50%, as both are not society members, while the publisher is a member of JASRAC and reported by ASCAP for the other 50%. For Stellar Stellar, it is Taku Inoue and Suisei's supposed name for 50% "other", with the second 50% being the same publisher situation.
Compare that to "Here Comes Hope":
View attachment 74157View attachment 74158
Ooshima Fumihiro is Tom-H@ck's, the songwriter, real name and reported as such in the song info. Sakakida Wataru is hotaru's, the lyricist, real name and reported as such. Hotaru is part of JASRAC, so 75% of the information is from ASCAP and only 25% is from Tom-H@ck who does not belong to a society.
All other Holo songs released in that time by that publisher all show the same pattern of "songwriter and lyricist credited this way", including Calli's songs we knew she wrote included as Mori Calliope with the musicwriter she collabed with.
So why does this matter? Well, Suisei did the lyrics for both those songs and the "writer and lyricist" sections in ASCAP and JASRAC have Stellar Stellar and NEXT COLOR PLANET list her alongside the songwriter in the "writers" credits, while on BMI's Songview she is missing as Hoshimachi Suisei and that other name is there in her stead, however both unique identifier numbers for her and the other name are exactly the same.
Conclusion: Songview claims it is a combination of BMI and ASCAP's databases, but the Songview search on both sites report a different name associated to the same unique ID number for the writer of for her songs.
ASCAP has the songs listed in their personal databases correctly with the credit as Hoshimachi Suisei and those entries report to the combined Songview databases. BMI does not have the songs in their personal records AT ALL, which means their version of Songview pulls the data on the songs is pulled from ASCAP's database.
I think it is legit and Cover massively fucked up somehow. She may have been originally credited for the songs as her real name in ASCAP and JASRAC, but it was fixed. Both names have the same IPI/CAE (Interested Parties Information/Composer, Author and Publisher) number. According to BMI and ASCAP's site, you can update your name associated with that unique number to change it to a pseudonym on request, which makes sense because pseudonyms are used often in the industry. I think ASCAP's version of Songview and their databases updated properly with her name, while the BMI version of Songview is the original credit before the name was updated.
Tldr: I think it is legit.