When I recorded Ashes on the sea, I sent, and continue to send Utah Phillips royalties. Same for The Band Played Waltzing Matilda; I send Eric Bogle his fee.
Considering the small market for our music, I doubt that anyone would get very upset if you record their songs. It costs money to fight, and we are too small to make it pay.
Now, that said, if you plan to sell a million or more, do your homework.
Arginine, very interesting name. Does it mean what I think it means?