Desculpem a demora, mas estive a testar algumas soluções e a que melhor se enquadra para aquilo que quero foi.
Instalei o Linux Mint 19 e depois.
sudo apt-get update
sudo apt-get upgrade
INSTALAR DOCKER + HASSIO
sudo apt-get install apt-transport-https ca-certificates curl software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository “deb [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable”
sudo apt-get update
sudo apt-get install docker-ce
sudo apt-get install jq
sudo su
curl -sL https://raw.githubusercontent.com/home-assistant/hassio-build/master/install/hassio_install | bash -s – -m intel-nuc
INSTALAR NEXTCLOUD
http://unixetc.co.uk/2016/11/20/simple-nextcloud-installation-on-raspberry-pi/
wget https://download.nextcloud.com/server/releases/latest.zip
sudo mv latest.zip /var/www/html
sudo apt-get -y install php7.2-gd sqlite php7.2-sqlite3 php7.2-curl php7.2-zip php7.2-xml php7.2-mbstring libapache2-mod-php7.2
cd /var/www/html
sudo unzip -q latest.zip
sudo mkdir -p /var/nextcloud/data
sudo chown www-data:www-data /var/nextcloud/data
sudo chmod 750 /var/nextcloud/data
cd /var/www/html/nextcloud
sudo chown www-data:www-data config apps
sudo /usr/bin/mysql_secure_installation
sudo mysql -u root -p
create user USER;
set password for USER = password(“PASSWORD”);
grant all PRIVILEGES on nextcloud.* to USER@localhost identified by ‘PASSWORD’;
sudo service apache2 restart
/var/nextcloud/data
sudo gedit /var/www/html/nextcloud/config/config.php
INSTALAR PLEX MEDIA SERVER
sudo apt-get update
wget https://downloads.plex.tv/plex-media-server/1.7.5.4035-313f93718/plexmediaserver_1.7.5.4035-313f93718_amd64.deb
sudo dpkg -i plexmediaserver_1.7.5.4035-313f93718_amd64.deb
sudo systemctl start plexmediaserver
sudo systemctl enable plexmediaserver
sudo systemctl status plexmediaserver
http://192.168.1.5:32400/web/
Assim, fiquei com o HA + Nextcloud + Plex Media Server instalados no NUC.
O Linux mint 19 por vezes é lento quando tento ver ficheiros no explorador, ou quando tento aceder à rede de casa, ainda ando a tentar ver isso, mas de resto, etá a funcionar muito bem.