WavPack has a number of versions, and, with the latest version, it can compress both PCM and DSD encoded audio streams, from mono to multi-channel. For PCM, it can be lossless or lossy (with "corrections" in a separate file to become lossless when combined). With PCM lossless stream, the samples can be integer or floating point values. Also, a file with .wv extension can be not only audio stream, but also an ISO CD image-like container with internal file system, with directory tree and several files, usually WV with audio stream, CUE and artwork, but also any kind of files.
So, Mango may support some kinds of wv-files, but not all of them. Neutron supports all.
FLAC only provides lossless compression for PCM streams with integer samples. The samples can be up to 32 bits, but most software players support up to 24 bits only.