There's another 2 coupleeee ahhh, is it still not here?

I presume you meant the other two couples in the 2nd to the last slide where they greet Happy New Year... They're actually from two different previous works of the author.

https://www.mangago.zone/read-manga/aisaretagari_no_gemini/

https://www.mangago.zone/read-manga/a_kiss_for_each_face/

Ohh i see, i thought it's in the same timeline lol, thanks (=・ω・=)