Would you cheer and offer to assist, if your local police started disarming, detaining arresting and taking ICE agents to local jail?

I would cheer if they were disarmed and unmasked. I don't think they need to be arrested. ICE are still federal officers. However, they are enforcing civil violations, not dangerous criminal violations. There is no need for them to be militarized the way they are. If they need to detain someone who is a violent criminal then that would fall under police or FBI and then they can handle the civil violations once detained.

If they actually operated like the civil violations enforcers they are instead of a paramilitary force I think most of the problematic aspects go away.

You're damn right I would.