BitCoin Linux Application / Proper method to set up 1 - Can I run the BitCoin daemon (before KDM is even started)?

2 - Once I've started KDM, can I then run the GUI which will attach to the daemon, so only one BitCoin 'app' actually working?

3 - Can you get a status report from bitcoin-cli, similar to the qt-app (status of catching/caught up with blocks etc...)

Following the BitCoin Install Guide , I ran the qt-app after installtion, it worked fine. I tried the daemon after and got issues with 'no cookies' / problem with rpc authorisation.  I've also stopped the qt-app, then tried the daemon, it worked fine, then tried the qt-app and it complained something was already connected to the default port.

What is the correct order of running it, note the machine is on 24/7 (minus the desktop).
1 - Can I run the BitCoin daemon (before KDM is even started)?


You can run the non-graphical bitcoind daemon with or without starting KDM first.


  2 - Once I've started KDM, can I then run the GUI which will attach to the daemon, so only one BitCoin 'app' actually working?


No. You can stop bitcoind and start Bitcoin-Qt, though.


  3 - Can you get a status report from bitcoin-cli, similar to the qt-app (status of catching/caught up with blocks etc...)


Yes. 

bitcoin-cli getblockchaininfo


(Source.)