Is there anything permanently missable? For example, in the Selky Pint, there's a bit that checks to see if I'm currently a Rogue. If I'm not, is the money gained from it permanently inaccessible?
Currently, I don’t believe there are any mechanical effects (like gaining money) that are permanently miss-able (unless there is a mistake/bug). In your example, for instance, re-rolling as Rogue should let you complete that encounter.
If I do create miss-able benefits in the future, the goal would be that they would occur from deliberate choices and have some kind of trade-off rather than result from simply failing encounters. But we’ll see.