Maybe they should be removed to correspond to the song version uploaded? It also makes the translation sound very weird...

For the line "Risu no minasusume kuri no hata", the official kanji lyrics certainly do have minasusume in brackets next to the kanji 'ko', but there is no way that it means you're supposed to actually pronounce 子　as minasusume. Actually I tried listening to hear if it was in the background or something but I couldn't hear any of the bracketed lyrics anywhere. It might be that one of the other versions of the song had that in it, but I haven't checked (there were a few versions on the single). I don't know the policy in this case though, because its pretty clearly that that is what the lyrics on the CD scans say, but its simply not what is being sung. So should the lyrics be left accurate to the (inaccurate) CD scan, or changed in order to reflect the actual lyrics?