There's much talk on "big life, small space" about New Directions characters getting crushes on each other. It seems logical that Blaine would get a crush on Sam. Sam would probably be cool with it, though it would mess up their "bros" dynamic. Blaine and Sam dueted together. In "Duets," both Finn and Burt discouraged Kurt from dueting with Sam. Burt didn't exactly know what duets meant, but he didn't want Kurt to put his attentions to where they might well be unwanted. Finn had a much better idea of what duets meant.
Blaine and Artie dueted, too, though their purpose was to cheer Brittany up. That would be the most interesting dynamic to me. I really don't think it would happen. Sugar's there. Artie does admire Blaine's talent, and has said occasional Ho Yay things. Well, I think everyone on Glee has said Ho Yay things because it's that kind of show, in spades.
I can imagine several characters getting crushes on Jake. Blaine would again be an interesting one to me. Jake joined New Directions knowing that Blaine was gay, I'm pretty sure. He knew Unique was a trans girl. Unique and Sugar have both said they think Jake is cute. Unique warned Marley that Jake was a womanizer. Unique getting a crush on Blaine seems to be a likely enough storyline. As I said a day or so ago, Blaine knows Unique is a girl. Jake would probably be cool enough with anybody getting a crush on him. Jake's decent like that.
Joe got turned on by Quinn. Joe said right away when he was introduced to the God Squad that he didn't know any gay people. He quickly enough got to know Kurt. If there was a crush for Joe, I think it would be a girl/boy crush in either direction. The thing is that the older members of ND have known each other for a while, and the younger members are already in love triangles.
I'm sure some femme slash has already been written about Kitty. She's very religious in a scary way. I don't think she could be anything but straight. It would be another interesting story if she wasn't. Marley is straight.
I don't know who Tina might get a crush on. As I also said recently, she and Artie already dated. Maybe one of the new boys? I'd like for someone to get a crush on Tina. I think she's cute.
I hope nobody gets a crush on Finn. I don't want that. I'm trying to think if he's dueted with anyone this year. He and Blaine sang a song, but they were in different states. Blaine went to Eli's house and Finn was with Rachel. Plus there was a year of Kurt having a crush on Finn.
The promo for next episode indicates that Sam crushes on Brittany.
Britt could get a crush on a boy or girl.
Marley, Unique, Blaine, Sugar, Tina and Kitty would get a crush on a boy. Ryder, Jake, Artie, Joe, and Sam would get a crush on a girl. My prediction is that it will be whatever are the most awkward and futile combinations possible. Sadly, that would include Unique having a crush on any of the boys. Blaine would be the most futile, but among the boys there's the best chance he'd be cool about it. Blaine getting a crush on any of the other boys would be awkward and futile, as would any of the girls getting a crush on him. We'll see who duets with who in the next couple of episodes. I'm getting the importance of dueting from You Gotta Let It Out, though I may not be understanding it right. I'm especially waiting to see who Unique duets with.