Each Blockstar has at least one, at most 3, musical skills on a scale of 1 - 100. A variety of different Musical Skills are required to form Bands (the specific Skills depend on the Genre of the Band), and some skills are much more prevalent / rare than others (for example, many more Band types require a Vocalist rather than a Ukulele player, making Vocals a highly important skill, but also more common among Blockstars).
High-talent, high-potential Blockstars with the maximum 3 Musical Skills will be much more rare than an average-talent, average-potential Blockstar with just a single, common skill like Vocals.
Musical Skills are organized, just like in the real world, by instrument group, and the skills of most multi-talented Blockstars will typically come from a single instrument group (for example, a multi-talented Violinist might also be able to play the Viola and Cello). The rarest multi-talented Blockstars will possess Musical Skills across multiple instrument groups (for example, Vocals, Acoustic Guitar and Keyboard), making them the unicorns of the Blockstar metaverse, truly the embodiment of the "one-person band!"
In addition to the Musical Skills within the 5 instrument groups, Blockstars can also be skilled at Vocals and DJ, which do not belong to any specific instrument group.
There are a total of 43 Musical Skills in the first 10,000 release of Blockstars - but wen bagpipes?
Musical Skills are required to fulfill Band Requirements. Some Musical Skills can be used as substitutes for others (for example, a Viola could substitute for a Violin), but they may not perform as well. However, a player with a Blockstar that is highly skilled at the substitute instrument might actually be able to put together a stronger band overall than if they used the primary instrument in which their Blockstars are less skilled.