Bill Murray
I'm still kind of surprised he finally agreed to do GB3 after so many 'no ways' over the past 25y
I wonder what finally got him on board?
I guess a big reason was he did the remake so he must've figured well I appeared in that POS (as he was open to giving the SNL girls an endorsement) I may as well slum it in the proper GB3 which can't be as bad. (him being in that kind of makes it abit like Arnold in Terminator Gensys/Dark Fate going from an almost remake to genuine sequel and as a result kind of takes away from the anticipation)
Also I guess there would've been the shame of not appearing (especially after Harold Ramis died) and everyone asking him in interviews to come for other stuff 'hey bill why didn't you do GB3?'- of course that applied to the remake too (I think thats a big reason Ford did Star Wars VII)
Talking of Ford and SW the old original actors coming back for the 'legacy sequels' is now very much the norm (which it wasn't a few years ago when Murray was being pestered to do GB3)
Also its not like he's besieged with movies offers now like before in the 90s when Aykroyd was sending him the GB3 scripts (which hed send back shredded lol). just the odd Wes Anderson movie (again similar to Ford being open to doing SW and Blade Runner again after his above the title leading man status had gone)
And of course lots and lots of money (same as all the old time actors revisiting their past roles for a nice little earner)