For your first issue, see if the April 2018 upgrade fixes it -- it's the first version that no longer requires port 4244. If that's not your solution, then this may help:
As I recall, I had to:
1. Set up a Virtual Proxy specifically for the monitoring apps
2. Change the security on some data connections
I don't know about nodes failing. Qlik Support, or your reseller support, should help you review the logs.