Once Upon A Studios done for Disney's 100th anniversary was noteworthy for bringing characters from both films and shorts done by Walt Disney Animation Studios of both 2D and 3D animation together, even as far as having memorable moments, of which we should certainly see again in the decades to come. Times they would work best at include other centurion milestones, like the 100th anniversary of Mickey Mouse in 2028, the 100th anniversary of the very first Disney Animated Feature Film in 2037, among others. I already started up a petition towards the end of last year about Mickey's 100th Birthday, being that something extra special not like those seen in previous decade accomplishments being done: https://www.change.org/p/please-be-sure-something-extra-special-is-done-for-mickey-mouse-in-2028

Such times would be a great opportunity for missed opportunities from Once Upon A Studios to be made use of, like in deleted scenes of that short. It's also an opportunity for characters who've not spoken more then a decade to speak, in addition to these role reprisals outside of archived audio:

*Matthew Broderick as Simba for first time outside main Lion King films. *Rowan Atkinson as Zazu for first time since film of origin (depending on reason why he hasn’t voiced him since then).
*Danny DeVito as Philoctetes for first since film of origin.
*Eddie Murphy as Mushu for first time since film of origin.
*Wayne Knight as Tantor for first time since film of origin (plus other VAs of that film who didn’t voice their characters since then).
*David Spade as Kuzco for first time outside films (only archived audio was used in Once Upon A Studio).
*Michael J Fox as Milo Thatchet for first time since film of origin.
*Among others.

Important it is though to keep character voices consistent with other media, especially with those who are currently voiced by experienced voice actors, though there are some recastings I personally wouldn't mind, for instance with other classic characters that Alan Tudyk could end up taking over as.