I finished the Game, did Aloth's quest, and never got beyond +1 no matter how many times he approved of my actions.
Tekehu hit on the watcher IMMEDIATELY, and I tried to put that on hold, never got the option to romance him after that. Apparently, it's one chance, and too bad if you say no 5 seconds after you meet.
It felt like there should have been WAY more party interactions? PoE1 had tons without the relationship system but Deadfire has scarcely any. If this isn't a bug, then it's a huge step backward.