Data Structure For Creating a Client Side Array of Contacts

My app allows users to create a list of Contacts via various searches, and then choose a set of actions on those contacts, such as sending them an email.

I’m a bit unclear about how to create the data structure to do this.

So far I have created an array of numbers called Contact List and used Add Unique to add the id of a chosen contact to the list.

With that I have created a repeat block which allows me to display… well, with my current knowledge, only the id values!

Is there a way I can access more useful information about the contact in this repeat, or do I need to create a more complex data structure that somehow gets initialised with fields such as first_name, last_name… when I do the Add Unique?

Thanks in anticipation!
Antony.