As far I can understand:
- GSettings / dconf paths are not equal for
gnome-terminal and mate-terminal.
- The files in repository are dated 2015, so they may not suite for modern terminals in 18.04 LTS. But it works in GNOME terminal from 16.04 LTS.
So it needs some patching. I did not edited author's scripts. I just detected what they change by comparing dconf dump / output on 16.04 LTS.
Adding new profiles
As the result below is the script which adds two new MATE Terminal profiles - One Dark and One Light:
dconf write /org/mate/terminal/global/profile-list "['default','one-dark','one-light']"
cat <<EOF | dconf load /org/mate/terminal/profiles/
[one-dark]
foreground-color='#abb2bf'
visible-name='One Dark'
palette=['#000000', '#E06C75', '#98c379', '#d19a66', '#61aeee', '#c678dd', '#56b6c2', '#abb2bf', '#5c6370', '#e06c75', '#98c379', '#d19a66', '#62afee', '#c678dd', '#56b6c2', '#ffffff']
use-theme-colors=false
use-theme-transparency=false
use-theme-background=false
bold-color-same-as-fg=true
bold-color='#ABB2BF'
background-color='#282c34'
[one-light]
foreground-color='#383A42'
visible-name='One Light'
palette=['#000000', '#E45649', '#50A14F', '#986801', '#4078F2', '#A626A4', '#0184BC', '#A0A1A7', '#5c6370', '#E45649', '#50A14F', '#986801', '#4078F2', '#A626A4', '#0184BC', '#ffffff']
use-theme-colors=false
use-theme-transparency=false
use-theme-background=false
bold-color-same-as-fg=true
bold-color='#383A42'
background-color='#F9F9F9'
EOF
After execution, closing terminal and opening it again you will get two new profiles in the drop-down menu:

The profiles look like as follows:
One Dark

One Light

Revert to defaults
To remove all custom profiles use:
dconf reset -f /org/mate/terminal/profiles/
Note: the method is suitable for both Ubuntu MATE 16.04 LTS and 18.04 LTS.