Who will be the leader of RiverClan at the end of ASC?

I think it will be Icewing as leader, her actions this arc make her a good candidate. She realizes that trying to fight Tigerstar IIs occupation is not really the best idea with no leadership to guide the effort, in the Battle for Riverclan, its very clear that Shadowclan is well led and organized. Even though Riverclan is fighting on their home terf, they cant stand up against a well led force. Working with him to guide the clan through occupation and give her clanmates a say is the best way to make the best of a bad situation. Call her a collaborator if you want but she helped keep her clanmates safe. Icewing is the one who came up with the compromise to have the Shadowclan cats hunting on Riverclan territory also hunt for Riverclan. She supported Frostpaws decisions even when they might not have been the best, like Owlnose as leader. When its clear that Owlnose isnt the guy for the job, she wants hm to step down and not continue the sham. She did spill the news about Frostpaw not being Starclan sensitive in the beginning, but this is something that the clan should know considering how big of a deal it is. From here, she still supports Frostpaw and rejects Splashtail. I think that given what we have seen, she does fit what Frostpaw is looking for in a kind, welcoming leader that wants to work with others rather than start conflict. 

I think Duskfur will be her deputy, as he has had a strong voice and a hand in helping Riverclans situation. He was chosen to be leader at the Riverclan/Shadowclan mediation led by Tree. The clan likely chose him because he is a strong advocate for independence while Icewing has been working with the occupiers. Icewing was also there but her and Duskfur were overshadowed by Splashtail. I could also see them choosing Owlnose as deputy because he just needs more experience to be a good leader one day.

It really cant be Frostpaw cause how can you go on a journey, talk to Riverstar, learn to speak to Starclan, just to come back and say "Actually, God told me im the best leader." That's ridiculous. Not to mention she has zero experience and is a baby compared to everyone else. It would also leave Mothwing as the only official med cat in the clan and she cant talk to Starclan, leaving the clan still as a "Starless Clan" in another way. I don't think Mothwing will be leader because that's the same thing as Splashtail, a leader who doesn't have a connection to Starclan.

After all of this, the authors will still probably choose Mothwing. Not because it makes sense, but because shes the only character in Riverclan that isn't a cardboard cutout named "warrior cat #31809B".