Hey,
Cool team, not much to suggest as you've obviously hammered out the weaknesses here. As Shurtugal said, Hidden Power [FIRE] on Latias should be replaced on Latias. As cool as it is to nail Scizor and Ferrothorn, your Heatran and Jellicent can both take on Scizor, and Ferrothorn is beaten up by Heatran and your own Scizor. I instead recommend you switch to Substitute instead. Substitute lets you avoid the status conditions that plague your current set, and can also be used to avoid U-Turns, by subbing as they switch out, giving you more opputunities to rack up Calm Minds until the point where you can comfortably sweep, free of status.
On Jellicent, Will-O-Wisp seemed slightly redundant to me. You can already spread burns with your Scald and Heatrans Lava Plume, so I didn't think it was the greatest choice in that slot. Instead, try out Toxic > Will-O-Wisp. Toxic lets you get special attackers and opposing stall based pokemon with a much more annoying status to handle, as they really don't care that much about getting burnt and can continue to annoy your team. Toxic lets you remedy that, with a more accurate and damaging status to inflict on them, which can help a lot in many situations, and can force every pokemon out quickly once the poison damage multiplier has reached too much for them to cope with.
GL with the team