What if I remove app?

If you simply remove it from sale, yes. If you delete the app completely, you aren't allowed to create a new app with the same name (although every other developer would be allowed to use that name).

I think you are mistaken. I clicked the option "Remove App", and I got a message saying that app name will be released to other developers and put in my removed apps list. I think you are correct that I can add that app back anytime, just that I might have to use a different name if another developer decides to use the name I had been using before I removed the app.

There is a slightly different new process, perhaps new since your thread was first started.

Some info here: Re-use deleted app name