How to circumvent music copyright when developing a game?

Question

Copyright

Hello, I want to write a game in the style of "Guess the melody", the problem immediately arose of the rights to play pieces of songs, of course, the game will sound the name of the song and the name of the artist. The size of the song pieces will be 3-5 seconds. Songs are needed Soviet or Russian before the 90s or 00s. I see several solutions:
1) Take a few notes from the songs, keeping the motive, write them down like on a piano. Is it possible to do so?
2) Change the key of the melody / some notes, but keep the motive. Is it allowed to do so?
3) use songs from the public domain of the Russian Federation. But I can't find the federal list of works in any way :(
4) Find a catalog of SS songs, but, damn it, they are all geared towards foreign music, not with Russian songs.
Who thinks about each item? Are there any other solutions?

Answer 1

Actually, the melodies from the songs in short fragments are completely subject to Fair Use in the DMCA if you leave links to the authors. In most jurisdictions, a melody consists of intervals between notes, i.e. tone doesn't matter.