Fringe executive producers Jeff Pinkner and Joel Wyman held a conference call on Wednesday to, first, thank those who write about television for their support over the years and how that, in part, helped the show earn a fifth and final season pick-up. Then they got to the business at hand: fielding burning questions coming out of the past couple of episodes and leading into the final two weeks of Season 4.

A MOST LOGICAL ENCORE? | For starters, TVLine asked the show bosses if what/whom we got a glimpse of in the 2036-set Episode 19 — coupled with what Josh Jackson said about the Season 5 storyline and what Walter is claiming in the new promo making rounds — means that the services of Leonard Nimoy will be needed come fall, to reprise his role as William Bell. Or, since Nimoy is semi-retired from on-camera work, are they writing themselves into a bit of a corner? “Once you kind of realize the extent of everything, it will probably become clear why we’re not [writing ourselves into a corner],” Wyman answered, cryptically. But that’s not to rule out a Bell comeback before the Fox series signs off for good after Season 5’s 13-episode run. As Pinkner said, “We basically erected a sign outside of Leonard’s house that says, ‘Please come back to Fringe,’ and we are hoping that by Season 5 he says yes.”

FUTURE SHOCK | The EPs stopped short of confirming buzz that Season 5 would heavily involve the year 2036 seen in Episode 19: “That future is important to our storytelling, but it’s the not the be all and end all.”

FALSE FINISH | Wyman rebuffed that which series star John Noble told reporters last month, that as a “back up” plan of sorts, a slightly different ending was filmed just in case the series did not get the Season 5 order. “We did not shoot an alternate ending,” said the EP. “We thought about it, but we did not [film it].” So do not look out for that DVD extra, folks.

ALT-DELETED? | Of course the big question raised by last Friday’s episode concerns the fate of the “red” universe and, by extension, series regular Seth Gabel, whose Lincoln Lee now only exists “over there.” Have we seen the last of him as well as [heavy sigh] badass Bolivia? Pinkner stepped carefully around that question, but did go on to note that the inter-universe bridge “is closed because of the problems that David Robert Jones is causing, so if our team can somehow dispense with Jones, there is absolutely a possibility of that door being open again.” And on the Gabel topic itself, “Seth is spectacular and awesome … but as for his standing going forward, to say anything about that would be also to reveal things that are coming ahead,” Pinkner hedged.

What burning questions do you still have about Fringe‘s fourth and fifth seasons?