Chord Overstreet  and Jenna Ushkowitz Chord Overstreet and Jenna Ushkowitz

Glee's Season 4 premiere on Thursday answered many burning questions (Can Cassandra July actually out-dance her wide-eyed ingénues? Yes, she can!), but it also left fans with a set of new ones . When the heck is Finn coming back? Is Tina going to be mean forever? What's next for Klaine after Kurt's teary goodbye? And most importantly, what other celebrity impressions can we expect from Sam next? We got the answers to all those and more:

1. Is McKinley putting on another musical? Loved the New Directions' performance of "Summer Nights" last season? Well, you're in luck because co-creator and executive producer Ian Brennan teased an upcoming episode that sounds to be heavy on Grease lightning. "Our Grease episode, which we just finished writing, I think, is certainly our strongest episode in a while," he tells "It just ended up really funny and sweet and weird." While it won't be a full-on tribute episode, a la next week's "Britney 2.0," Jenna Ushkowitz offered a few more hints. "There's a possibility of a musical and we may be putting on a show," she said. When asked if it would follow in the footsteps of last year's West Side Story production, she said "perhaps, yes, definitely." As much as we loved Sam (Chord Overstreet) as Danny Zuko, we're pretty sure new girl Marley (Melissa Benoist) and resident bad boy Jake (Jacob Artist) have Sandy and Danny written all over them.

Glee's Ian Brennan: Season 4 feels more "adult" and goes back to basics

2. Is fierce Tina here to stay? Don't go casting Tina as Rizzo just yet, because she might lose that new 'tude she developed over the summer as fast as she gained it. "She's a b---," Ushkowitz says with a laugh. "I'm sort of going for it because they're writing for it .... but I think she'll be brought down real quick."

3. Is Finn heading back to Ohio? Although some would have guessed Finn (Cory Monteith) would be headed straight for NYC to see his beloved Rachel (Lea Michele) as soon as he finished his Army duties, it sounds like he'll be back in Lima. "There's some fun stuff with me and Cory that's coming up," Overstreet says, also adding that he hopes to see Sam back on the swim team this year. "Those are so fun — doing those ... swimming scenes," he says.

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4. Who will Sam impersonate next? Ask, and ye shall receive! Sure, Trouty Mouth has a beautiful singing voice, but he's quickly becoming more well-known for his spot-on impressions of celebrities ranging from Sean Connery in The Hunt for Red October to Taylor Lautner via The Twilight Saga. And that's just the beginning. "I may throw a Christopher Walken out there. I may do a George Bush. Anything goes as far as the impressions go," Overstreet says. "A lot of times, we'll get there on the day and ad-lib some stuff so who knows."

5. Is Blaine off the market? Things may get bumpy for Klaine now that Kurt (Chris Colfer) is in New York, but Darren Criss is confident about their long-term future. "I think we've set up the fact that they are the couple that people like, so we have our Ross and Rachel," he says. "Regardless of if they are together or not for the rest of the season, it's going to be that exciting [relationship] that you always want to happen, so to me that's like a victory." If the two go their separate ways, however, Criss sounded none too keen on the idea of a new love interest. "Ew, I hope not," he says. "He better be really cute."

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6. Will Sue finally lay off of Will and the glee club for good? Yeah right. "It's a little interesting because having a baby made her mean again for some reason so she has a little bit of that anger back at Will again," Matthew Morrison says. "There's a little toe-to-toe action this season." And you know the best way to work out that tension? Through song, duh! (This is Glee, after all.) Morrison says he and Jane Lynch will sing an "obscure" Irving Berlin tune together in an upcoming episode.

7. Who's next on Sam's dance card? He's romanced Quinn (Dianna Agron), Santana (Naya Rivera) and, most recently Mercedes (Amber Riley), so who will Sam woo next? "I've heard little bits and pieces of Ryan [Murphy] dropping hints of love stuff here and there," he says. However, he did shut the door on a possible reunion with Mercedes. "I think that ship's probably sailed. I think she's in L.A. doing her thing and Sam is good with her following her dreams."

8. When are the old seniors coming back? Artist says that many of members of the Class of 2012 have been popping up on the McKinley set. "They all kind of have their own story lines post-graduation so it kind of works seamlessly with what they're doing," he hinted. Does that include his half-brother, Puck (Mark Salling), who has yet to find out about Jake? "You might just see one," Artist says. "I think it be cool to see the dynamic between the two of them when they meet for the first time."

9. Will Emma and Will make it to the altar? Before they say "I do," the happy couple will have to endure some bumps on the road. "This is the first time that they're actually living together under one roof and I don't think it's as easy as Will thought it was going to be," Morrison says. "There are some growing pains and it's a little tough."

Glee airs Thursdays at 9/8c on Fox.