Check posts under a custom taxonomy for other custom taxonomies

Hello,

Hoping someone might be able to help with what I am trying to do, or let me know it isn’t worth the trouble 😉

I have created a custom post type (Project), which has two custom taxonomies (Capability and Client) registered to it. Everything is working great.

What I am now trying to do, is list out all of the Clients, and for each Client loop through each Project that has been tagged with it to see if it has been tagged with a Capability.

The end goal is to create an unordered list of clients, with each list item having a set of classes indicating which capabilities were employed for them. ie:

<ul>
	<li class="capability-one capability-two">
		Client One
	</li>
	<li class="capability-one">
		Client Two
	</li>
	<li class="capability-two capability-three">
		Etc.
	</li>
</ul>

My attempts have fallen short as I’m not too great with PHP or WordPress Templates, but here’s the direction I’ve been trying to get a quick and dirty list of classes:

[Code moderated as per the Forum Rules. Please use the pastebin]

Any help would be greatly appreciated!