Microphone: I spent 90% of my performing career hating my sound coming out of sound systems. It honestly was to the point where if it was a gig that required a sound system, I didn't want to do it. Two years ago I splurged and bought a DPA 4099U. It attaches to the bell of the clarinet (facing up towards fingers, not into the bell) and still manages to pick up an even sound up and down the clarinet. The sound capture is unbelievable, to the point that in-studio professional sound engineers have preferred it over their gear.
Neckstrap: Most clarinetists don't use a neckstrap but I HIGHLY recommend it. Even though the clarinet is relatively light, over time the downward pressure can cause hand problems. There is another significant benefit that I think isn't often talked about with neckstraps: the clarinet exerts downward pressure on the thumb meaning that your hands and fingers have to compensate for that pressure. For me, once I started using a neckstrap, my fingers and hands felt more at ease, and my technique, accuracy and agility improved noticeably. Probably most clarinet neckstrap products will do but I've owned the next strap below for 10 years and it's been great for me. Plus, I highly recommend combining it with the "Neckstrap extension rod (ring mount)" here. I find the angle created with any other neckstrap solution to be problematic.
Many have asked me about sheet music for Flight of the Bumblebee because of my Youtube videos. I came across a site called Virtual Sheet Music. I ended up buying $25 of music and decided to go with the year subscription for an extra $12. Now this allows me to download unlimited amounts of music for one year for free, which I think is a pretty sweet deal.
They have a version of Flight of the Bumblebee for clarinet and piano that I recommend HERE.