I had been waiting to see if Community would be picked up by some non-NBC entity before I got around to my post-Season 5, pre-Season 6 coverage, and now that Yahoo! has come through, we can speculate on whether any guest stars from Season 5 ought to be held onto, and if any of those from Seasons 1-4 should be retrieved for another go-round.

Rachel
Rachel

As soon as Brie Larson first appeared in Season 4, I was leading the call for her to return and even potentially become a regular in the cast.  I still feel that way, and now, it’s less a matter of her acting ability (which is still great), and more a matter of logic.  Rachel and Abed are now dating, and they seem to be happy, so it just wouldn’t make sense for her not to be around very often.  But apparently Brie Larson’s movie career is taking off, so her availability may remain an issue.
Verdict: Lock her down before she becomes prohibitively unavailable!

Russell_Borchert
Russell Borchert

Greendale’s founder, previously presumed missing, had spent nearly 40 years hiding in a bunker underneath the school.  Now that he is back aboveground and heartened to discover that the “idiots won,” he may be interested in staying involved with Greendale’s affairs.
Verdict: Chris Elliott would be a perfect eccentric fit as an occasional-to-frequent presence.

Ian_Duncan
Ian Duncan

Duncan has always been a regular presence, excluding election and Dan Harmon-less years.  There’s no reason that should change, though it may have to, due to John Oliver’s HBO gig.  But he has expressed a desire to return if he can fit it in his schedule.
Verdict: Let’s pencil him in for at least one day at gravedigger’s biscuits.

Community - Season 5
Buzz Hickey

Like John Oliver, Jonathan Banks was a Season 5 semi-regular who now finds himself with a new full-time gig.  Better Call Saul‘s premiere was pushed back to 2015, and Yahoo! apparently wants Community Season 6 to debut this fall, so he might be able to do both, or maybe those schedules will actually end up overlapping too much.  This wouldn’t be the biggest loss, because now that the Save Greendale Committee has achieved its goal, Hickey wouldn’t be required to hang out with the study group.  Still, it would be jarring for him to disappear completely.
Verdict: Make the time work for at least a token appearance.

Troy_LeVar
Troy

A sailing trip around the world will last a while, but it won’t last forever.  Surely Troy will visit his friends upon his return, won’t he?  And Donald Glover has sounded at least somewhat willing to return during his recent public appearances.  Although, that Easter egg of Levar Burton and his non-celebrity companion having been kidnapped by pirates could explain keeping him away indefinitely.
Verdict: Troy will be back at some point, right?  If not Season 6, then the movie, right?

Hologram_Pierce
Pierce

Pierce Hawthorne has been known to fake his death, so a retcon of his most recent departure would have precedent.  However, “Cooperative Polygraphy” was too poignant for such a switch to be a good idea.
Verdict: He shouldn’t be forgotten.  If Chevy is willing to make the time, flashbacks or holograms could be employed.

Community-saison-4-Giancarlo-Esposito-de-retour_portrait_w532
Gilbert Lawson

Now that Pierce is gone, there is no clear direct purpose for his half-brother to show up.  But last we saw of him, he was on good terms with Pierce’s friends, so I wouldn’t rule it out.
Verdict: There is a potential storyline here worth considering.

Slater_is_flustered
Michelle Slater

Slater’s return wouldn’t serve much narrative purpose, as any lingering romance she may have with Jeff wouldn’t fit with where that issue stands now.  But she did kind of suddenly disappear.
Verdict: I’m interested in finding out what’s up with her, but wary about how that could fit into Season 6.

Vaughn_serenades_Annie
Vaughn

See Slater, minus the unexplained sudden disappearance.
Verdict: Unless the gang is attending the National Hacky Sack Championship, Vaughn’s story is finished, and it ended on good terms.

Community_Nurse_Jackie
Nurse Jackie

Does Jackie still work on Greendale?  I wonder what he of all people has to say about how all the times the campus has been destroyed.
Verdict: I’ve never been disappointed when Patton Oswalt is on my TV.

koogler
Koogler

Proving Mitch Hurwitz’s acting bona fides, the Koog was the funniest new character of Season 5.
Verdict: Koogler was a great one-off, but he probably wouldn’t work as well outside the context of the MeowMeowBeenz dystopia.  But is there any manner by which we can see his eponymous movie?

Anthony_Edison
Anthony Edison

Anthony doesn’t seem the kind of guy who hangs around for too long, though it would be nice if Annie were closer to her family, and her brother seems like the most likely place for that to start.
Verdict: We’re going to meet Annie’s parents eventually, right?  Anthony could be in that episode.

William_Winger_finally_appears
William Winger

Season 4 hit one of its strongest emotional beats when Jeff confronted his dad.
Verdict: James Brolin acquitted himself well, but William Winger did not.  Jeff’s life is fine without his father a major part of it.

Willy_Junior
Willy Winger, Jr.

Willy, Jr., however, is on good terms with his brother.
Verdict: Adam Devine’s vibe is a little off-kilter for Community, so I’m not overly pulling for his return, but I can see a scenario in which he could work.

Community_Andre
Andre Bennett

Shirley announced that she and Andre were separated again in “Repilot,” which presumably was meant to set up a storyline in which they attempted to reconcile.  My guess is that either time constraints or lack of Malcolm-Jamal Warner’s availability prevented this from happening.
Verdict: Andre needs to be high on the Season 6 priority list.

Community_Kumail_Nathan
Bob Waite and Lapari

There was some disappointment that after all the hype, Nathan Fillion and Kumail Nanjiani’s guest spots lasted all of about 5 minutes in an episode crowded by guest stars.  It’s not like their roles were designed to be huge parts, but since they are such awesome people, they left us wanting more.
Verdict: Jerry Minor and Eddie Pepitone have popped up a handful of times as the janitorial crew; why can’t the same be true of the custodians?

community_Levar_Troy
LeVar Burton

LeVar’s return is presumably tied to Troy’s.  Hopefully the Reading Rainbow revival won’t be too time-consuming.
Verdict: Stay in touch with Donald Glover, LeVar.  Make sure he’s not going too crazy.

fred-willard-in-community
Fred Willard

Fred Willard is just as much of a living comedy legend as Chevy Chase, but without all the grief.
Verdict: He wouldn’t even have to play Alter-Pierce again!  He could play anybody!  Fred Willard works in any situation!

Skipping_over_sprinklers_with_an_ice_cream_cone
Eustice Whitman

Accounting is an important skill in life.
Verdict: Come on, John Michael Higgins, seize the day!