Johnny probably still solo's.
The cold wouldn't do anything to GER. All attacks are stopped before the occur regardless. He's just too OP. Only his life-giving power could be effected. Plus the Skywalkers can't even see Stands anyway so it being a little less powerful wouldn't matter. That applies to standard Gold Experience too.
Joseph is probably near-useless here. He would only serve as a distraction unless he had Hermit Purple and even then.....
Johnny, Giorno, Jotaro and Jolyne take it pretty easily though.