After Ardor has been released, how will be the future development of Nxt itself. Will it stopped and all the resources will shift to Ardor or is there a further development?
Nxt will still continue to life. It's like a living organism. It can only be killed when all the nodes stop supporting it. The developers will update/support Nxt for one year or so. Maybe new devs continue Nxt, nobody knows. It's there and very usable.
Is there a trustworthy public NXT node?
http://212.47.249.50:7876/index.html(
never fill in your passphrase on a public node!!)