Depends -- it's folk-like if it's say AMerican Pie, but if it's ANnie's song, it's "folkoid". My reasoning is that foksongs survive the centuries because of a certain combination of qualities, imagery and spirit as related to raw experience. When they succeed in transmitting a part or all of that actual experience, through the use of whatever rhetporical or aesthetic device, they are like successful "memes" which are reproduced and carry forward.

However to take an impression of those qualities, and then write something which seems to match that impression, is like ... oh, maybe like designig a house based on an inspiring wallpaper. You then get the derivative and less robust form called folkoid in my book -- seeming to touch the bases but not quite able to carry the weight of the genuine process.