CAMERA: My first camera was the Sony Handycam, which is probably most similar to the Sony CX405. I currently use the Sony a7m3. The kit comes with a zoom lens, which is probably your best bet starting out.
AUDIO: Rode wireless lav and on-camera shotgun mic. Rode just announced a dual-transmitter wireless lav mic system. I haven’t tried it, but if I didn’t already have a Sony version of this, I would totally buy this Rode system. I should add that good headphones that cover your ears are also important. I use Sony MDR7506.
Drone: DJI Mini 2