I've been thinking about this and I don't believe the Makeb "romances" can be as in depth as the non-companion ones in game now.
From what I understand, none of the Makeb content is class and character exclusive...so all dialog choices will come down to a roll for up to 4 people in a group. The non-companion romances used in your example had dialog exclusive to an instance and the owner of it. It would be kind of odd if four players were romancing the same NPC over the course of Makeb's story.
So, it has to be like some of the shared flirt opportunities we have now with random NPCs and will be subject to a roll if you are in a group, which aren't deep at all.
Well, I can tell you this, and I believe this has been brought up in the thread before, but when I've seen people encounter npc romances in groups, the romance option just doesn't trigger. You can't roll to win to sleep with Darth Lachris. It won't happen. For Makeb, even though we know we aren't going to have class stories, there could in fact be class instancing still. But even if there is not, there's a good chance that they've thought of these things. There are some non-class quests in the game that you can't share with other people (like the ones tied to operations). So we'll have to wait and see.