The difference between @blockstream Liquid and Fedi seems to have more to do with how a token (vUTXO or an eCash token) can be transported. A eCash token doesn't need a network connection to work, Liquid does.

But in terms of trust both systems, Liquid and Fedi are similair.  

 Eventually, perhaps we see interoperable ecash between BTC and LBTC. I would assume there is nothing preventing liquid ecash.