You were better off before your edit. '(Does) that seem fair to you?' is fairly common. '(Does) it seem fair to you?' not so much. This kind of sentence would come after stating the terms of perhaps an agreement or the relating of circumstances. 'Does that...' demonstrates the distance between the situation and the speaker/listener. 'Does it...' would have to come before the telling.
1. We have to work this Saturday. Does that seem fair to you? I could imagine this shortened to: We gotta work this Saturday. That seem fair to you?
2. Does it seem fair to you that we have to work Saturday? I don't see this shortened, unless we also leave out 'it': Seem fair to you we gotta work Saturday?
Eliminating the does is fairly common in very informal, spoken American English.