Letter rankings don't express my feelings thoughtfully, but yes xmf is F tier.
Volcano get's it's own tier because it heavily depends on the people playing. Realistic placement would be like C tier, because yeah the minigames are a hike and a half away from cell area. Doing climb every round or waiting 10 minutes for that one rebeller to finish the secret is also not fun.
Link used if I shouldn't be in the kitchen, and you can cook better; https://tiermaker.com/create/tf2-jailbreak-maps-15982779