Iris says that Barry travelled to 2020 to discover Savitar's secret identity. However, in the relevant episode The Once and Future Flash (2017), he travelled to 2024.
Caitlin says that Gridlock's powers won't work in zero gravity because zero-G means no kinetic energy. Bodies have kinetic energy by virtue of being in motion and bodies can certainly be in motion in zero-G. For example, astronauts.