Frankly, I don't think the definitions in (4) helped me much.
The more I think about the role of music the more I have to ask the big question: How important is music for worship? For people who define worship by music, it's all important. For them, praising God with music is so primary that when different "tastes" are catered for separately, the outcome means more people worshiping. More people satisfied by music = more worshipers.
As you might guess, I want to define worship as much more than music. So much more! Rather, it's the full-bodied response as a whole people lives for God's glory. A holy nation, royal priesthood, once not a people but now a people, because belonging to God they live differently (1 Pet 2:9-12). Not just by the way they sing, nor only on Sundays in services, but by the quality of community - offering lives as living sacrifices (Rom. 12;1,2) within gathered worship, and (most vitally) flowing out. Here the outcome is not measured by numbers of people singing, but by a church's quality of unity, love and mission. And that is a very different measure.
So the crunch comes if music, seen as primary, is allowed to divide up people, and contribute to disunity, spite and complacency. What irony - music as worship ruins God's plans for worship! Music choices, just because they are often so visceral and emotive, can actually stop people maturing together. I believe that dealing with music in worship, where churches have strong divided opinions is the contemporary proving place for the work of the Holy Spirit. Nothing shows God more at work, than being open to worship that inclusively enables unity, love and mission. This means much Holy Spirit fruit, plenty of skilful preaching leadership (see 360degree leadership!) and always a willingness to keep maturing into Gods' big picture of worship.