Your claim that
The theme has a launcher at the bottom and custom icons to go with it.
is wrong. GNOME theme include only the gtk themes. The screenshot may include some other programs which may not be part of the theme. For example, the background image also isn't part of the theme.
But if you want to have the icon theme and the launcher, you can follow the steps:
Add the ppa
ppa:noobslab/macbuntu and install the
sudo apt-add-repository -y ppa:noobslab/macbuntu
sudo apt-get update
sudo apt-get install macbuntu-os-icons-lts-v7
I've known from your other question that you're using Zesty, and you needed to use
yakkety release on the ppa source file. So, in that case, you should be able to install
macbuntu-os-icons-lts-v8 icon instead.
The launcher is plank. Install it with this command
sudo apt-get install plank
Install the specific plank theme using this command
sudo apt-get install macbuntu-os-plank-theme-lts-v7
You should be able to use the icon theme and configure plank with the specific theme now.
(Same here too. You should be able to install
macbuntu-os-plank-theme-lts-v8 following the advice on your other answer. If you do so, you can have very identical configuration as the screenshot of the theme)