Bedrock autoloaded mu-plugins failing to load resources

Hi there, first off let me say Bedrock and Sage are brilliant, don’t know how wp sites were made before this! I’ve purchased the “Developing with Sage” book, I hope there’s plans for a Bedrock book? I would definitely be interested.

Question about the autoloader functionality of bedrock, I’ve installed some plugins using composer and forced them to be installed into the mu-plugins directory. So I have a file with something a bit like this:

"require": {
    "php": ">=5.4",
    "composer/installers": "~1.0.12",
    "vlucas/phpdotenv": "^2.0.1",
    "johnpbloch/wordpress": "4.2.2",
    "wpackagist-plugin/types": "^1.7.5"
},
"extra": {
    "installer-paths": {
     "web/app/mu-plugins/{$name}/": [
    "type:wordpress-muplugin",
    "wpackagist-plugin/types"
  ],

Which works fine, the only problem is the admin page for said plugin can’t load any of it’s resources (css, js, images, etc.) as it’s looking for them in, for example:

http://mydevsite/app/plugins/types/embedded/resources/css/ 

Have I set this up incorrectly? Or should the plugins be installed in both the plugins and mu-plugins directories (seems weird). I don’t believe this is an issue with the plugins I’m installing as I’ve tried several fairly wide-used and (I hope) responsible plugins.

I searched these forums before posting, so I hope I’m not asking something that’s been covered before, any help would be appreciated, thanks.