I don't work for Medium, but I'll do my best to help answer your questions based on my experience.

1) No

2) You should read first before clapping. It might look inauthentic to clap on an article before reading it.

3) I don't know, but most people aren't interested in reading long articles, so that's probably why they have a lower read ratio compared to shorter ones.

4) I wouldn't do it because it can be considered rude or it might look like spam if you do it a lot of times.

5) Yes, it helps a lot with improving the read ratio.

6) No, you should be genuine and you won't have anything to worry about. Accounts can get suspended at any time and it's not limited to the first 10 days of the month.