I don't think either are vetoable. There could be legitimate reasons for both, although I don't agree with them. For #1, Hafner doesn't have 1B -eligibility, and might need a first baseman. Hafner for Fielder straight up I could justify a veto for, but Rios has a shot at 25/25 or 30/30. I'd rather have the Hafner side, but I think it isn't vetoable.
For #2, the owner who has Santana may have too much pitching on his team. It isn't as if Holliday and Baldelli are scrubs. Again, definitely want the one side(Santana), but its not rising to the level of vetoable.