Thank you for the kind words! There will definitely be more of Julian. He's not a romanceable character for backstory reasons, but he is still considered a main character and will have his own storyline.
There will be Julian content in the next update, but the more positive version (including a new CG) requires not hooking up with him. You will still be able to get that CG later on if you did hook up, though.
I've divided the next several updates to focus on a few specific characters at a time to help me release updates quicker. The next update primarily features Matt and Evan with Leo and Marco having some significant stuff as well. Most if not all of the guys will still have some content in each update, however.
Julian will get his own featured update during Week 1 that will also focus on Owen. As the game continues, he'll have stuff that involves Matt as well, so you'll have interactions even if you don't focus on him. The way those scenes play out will of course be totally different based on your choices - Matt will be protective of his bff, after all.