VOCALOID is a trademark of Yamaha Corporation. Any product not designed for Yamaha's singing synthesis engine, is not a VOCALOID product. This also applies to other company's trademarks for their synths, like CeVIO. So a product can have a past as a VOCALOID product, and it's current development be for SynthesizerV, vice versa, etc. The characters, though used to sell third party voicebanks, are separate from the software in a sense. Sometimes, the companies that own these characters will use them for merchandise, games, etc., which has almost nothing to do with the synth product as the sole focus is the character. For example, Flower, the character representing products like vflower and flower talk, is featured on merchandise. People may purchase these products because they're a fan of the voice or the character, though the latter is usually the primary reason.