I know that Chloe don't return in finale but I think that she maybe appear someway because what end without Chloe . Also Lang don't return in season finale because Kristin Kreuk don't back . But I think that Lex , Lionel , Martha , Jonathan , Kara , Zod , Lara-El , Jor-El , Perry , Darkseid , Brainiac 5 and all live members of Justice League appear in season finale episode . It's also possible that Pete return someway.
So it's my list who return in show finale episodes.
Special Guest Start
archyve footage(all who appear in archyve footage)
Clark fly as Superman and he remember:How Martha and Jonathan find him . He are in car with Jonathan , Martha Lionel and young Lex . Chloe and Pete show Clark wall of weird . Lana(in alternate timeline) and Jonathan die . Whitney attack Clark and make him as Scarecrow and Tina appear as Whitney . Nancy , Lois and Chloe saw how Clark used his powers . Martha return . Clark save Lex from drowning and Lex briefly seen as one second from episode Arctic and that all back normal and many people:Martha , Oliver , Tess , Lois , Pete , Lana watch Clark who fly as superman (this is last sece)
Scene with Chloe:Lois have Call from Chloe who voice are hear but she are don't seen.
Pete return: Pete appear in one second when he watch Clark who fly as superman.
Lana appear:Lana appear same style as Pete.(but she are uncredit and unknown actor who play her)