Hi Ben
First thing I'd do is try switching to the develop version of the iform module. It includes a version of inlineJs. Here are some rough notes I wrote for getting D8 and Indicia up and running:

1)    I follow the instructions for setting up Drupal & git: https://www.drupal.org/node/803746. I skip the step “Creating the Central Repository” since I use GitHub, add my GitHub repo to the remotes as described under “Updating the remotes”. When it says create a working branch, I create one called “develop”.
2)    When I get to the point where Drupal 8 is installed, I use git to grab the Indicia code:
git submodule add https://github.com/Indicia-Team/drupal- … -iform.git modules/iform
git submodule add https://github.com/Indicia-Team/drupal- … atures.git modules/indicia_features
git submodule update --init --recursive

3)    You’ll then want to switch to the develop branch on the iform module (which works well and includes the inlineJs code):
cd modules/iform
git checkout develop
cd client_helpers
git checkout develop
cd ../media
git checkout develop
cd ../../../
4)    I then use Drush to download other modules, or use the Drupal UI.

I’ve found that the D8 version of AdaptiveTheme is pretty good, with nice flexibility and support for Sass, so I’ve been using that:
drush dl adaptivetheme
drush dl at_tools
drush en at_theme_generator
Then check the documentation on this at http://docs.adaptivethemes.com

You should find all the basic functionality works.
Regards
John