is this a normal process for job interviews?

Definitely not normal in my experience. Usually you will hear back next day at the latest, often even on the same day. Clearly they're struggling to make a decision, likely between two or three candidates. Even so they shouldn't contact you stating they're 'ready' to make a decision, they should contact you when they've made their decision!

It sounds like they offered the job to one or two other people and both turned them down so they are down to you, their third or forth choice. I would not want to work somewhere if they didn't feel I was a good candidate and only chose me because everyone else said no.
You should apply other places and forget this place. Either they are confused and don't know what they need, they don't pay enough or they have bad reviews. Move on.

There first choice may have changed their mind so they maybe reviewing the candidates again. We can only guess what is going on. The bottom line is that if they want you they call you. Calling them just wastes everyone's time.

No, they may be having a tough time trying to decide between a few candidates. If you were successful you would have heard some thing from them. Follow up with them again and maybe apply to a few more places just in case.