I think you should stay with one niche.

I also think you should do some research for which one of those topics (niches) you can monetize the best (ie affiliate products, your own products)

Stick with one. If you become general early, you can/will struggle to get readers/followers. Customers are looking for specific information for a specific topic. If you are all over the place they will leave and go somewhere else to find the info.

What do you mean by "niche or no niche"?

3 out of the 4 of these are / can be one niche. Making better beats - how to make those beats into teaching tools and how to make money with those beats online.

Do you see how these topics parrallel themselves? Your primary all in content move should be making better beats - notice I have removed "Rap" because the truth is you can create universal content "Making Beats" and then you can niche down into "Rap Beats" "techno Beats" dubstep beats" etc etc - this turns your "making beats" content evergreen - as it will apply to all the above.

Once you have a tribe / following... you can then throw at them content and an ebook on how to make money with beats. You can then target "Teachers" with how to introduce beats into reaching thier kids... because you started a bit wider - how to make beats and built that up.. you are then drawing in these more niched down topics ( Making money, and education ) into a diverse and thriving community.. IE street cred or as we say here Authority IE TRUST

Hope that helps!

And as a side note... part of that Hip Hop culture is Fantasy sports so sprinkling in your picks would not be so out of place.

I think from personal experience, niche blogs have had long term followers than no niche. it's because people already know what's the in bag so they'd definitely wait for something new or latest updates... niche sites are also great for groups right now, i.e people who does mountaineering etc.... they rely more on specific details rather than just a generic one.

A niche site is easier to rank on Google as opposed to one with various unrelated content. Niche sites are also more targeted, giving higher visitor value overall

I would go the niche route to start. Build up one site then after it's a decent size then move onto the next.

My best advice... No niche! We're human beings with tons of different interests and passions. Allow your brand to define who YOU are, not just be a part of you. Much love!