Liquid is custodial. Lightning is not. 

Federated, just means custody is shared. But it's still custodial. 

Liquid is no different to the Mutiny wallet federated severs, or CashU federated mints.  Liquid custody is done by a bunch of exchanges that I wouldn't trust with my Bitcoin anyway.  

I've put five bucks worth of Bitcoin into CashU mints which is more than I trust with Liquid. 

My major concern with Liquid is the way they pretend they aren't custodial.  At least CashU mints don't pretend to be non-custodial.