I'll have to test out the updating, sorry we we are still on Beta on N1 and the current install method is meant to be only temporary. But yes if you 'have never installed MinimServer' then it will wipe any existing SongKong and MinimServer installations as they used the same installer method, so unfortunately you'll have to reinstall MinimServer, but this will mean if you then install SongKong you will get 5.12 version (should be 5.13 but not because of other problem).
Updating from Previous Version I have just tested this and I found that following instructins for If you have previously installed SongKong or MinimServer on this Melco N1 did cause the previous release (5.12) to be replaced by new release (5.13) correctly.
Hidden anas.bak file on Mac If you unzip contents of zip file to usb drive then this folder should be copied regardless of whether hidden or not. I can only see an issue if you unzip to a temporary location on your hard drive, and then copy the visible files to the usb drive from there.