Hello, I'm a CW newbie, and I'll try to answer your question:
A1. Most people typically achieve speeds between 15 and 25 words per minute, but I've noticed that most of those I hear are around 18 wpm or higher. I personally use a speed of 20 wpm. Regarding learning speed, many people advise against going too slow and recommend maintaining a speed of 20 wpm for listening; however, I started at 15 wpm (characters) / 10 wpm (effective), and gradually increased my speed after completing everything. Currently, I feel that this method works well for me. Ultimately, the best learning method is the one that suits you best.
A2. When I was learning, I would listen to someone speaking Morse code and try to write it down immediately. If there were delays, I had to practice memorizing the codes (essentially creating a temporary "cache" in my mind, similar to how humans store information – haha!). Learning Morse code as a new language, associating the sounds of dots and dashes with their corresponding letters, can be a more effective way to overcome the challenge of counting.
A3. I think it's better to learn the code first and then start recording, because automatic key presses are generally quite fast, and if you're not familiar with the code, you might get stuck – while slower-speed automatic key presses seem less interesting and unnecessary to learn in advance. As for manual key presses, since I don't have experience, I can't really recommend or discourage practicing with transcription. However, I highly recommend learning from experienced seniors, as incorrect posture can lead to bad habits.
Best of luck!