>"Now you are saying sending tokens to other mints makes it custodial again."

No, I'm saying if another party operates within your mint, using your token, it is custodial. The act of them redeeming it on lightning or onchain, means it is no longer ecash on your mint. I feel you are conflating the redeemed bitcoin with ecash.

>"At some point in an exchange, money/value/tokens, is in someone else's custody"

You are being somewhat semantic here. Of course it is in *someones* custody, but there will be many more counter parties with IOUs that do NOT have custody.

The only time ecash is private is when you are transacting WITHIN a mint. And 99.9% of users will be doing that custodially with a "third party mint" as you say. Otherwise it is pretty pointless.