My pleasure, really!

The contact thing in Blixt seems to be essentially storing payment info (such as a Lightning Address or LNURL-Pay link) under a contact name. So it lacks automatic updatability, but can still be very useful for frequent payments.

I'm not sure what you mean regarding the LSP opening only one private channel with each user. That's pretty much what Phoenix does already with splicing, resizing the channel every time its needed. But it's not possible to receive a 10 sats payment for the first time, because it doesn't cover the on-chain fees of opening a channel. So the idea behind a "mixed solution" is that the LSP would take the Lightning funds for themself and send the user e-cash tokens instead. Once the user's balance is big enough (say 10k sats), the LSP will open a private channel with them. If many users reach this balance threshold approximately at the same time, it becomes possible for the LSP to batch the channel opening of many users into only one bitcoin transaction.