Right, if the framing of the scenario/resolution I proposed works for you in abstract, why not let the player make the call once they’ve established the fictional situation and you’ve set stakes and consequences? I really only see 2 solutions to your OP goal: you push for OSR style play, creating a table of extensive conversational exploration and largely ignore the 5e mechanics unless there’s serious uncertainty (or you’re a spell caster; OSR spellcasters are far more limited then those in 5e). This can absolutely work - an entire play culture proves it does. 5e’s rules probably aren’t the ideal way to do this, and you’ll be fighting culture for a while until you get it all set up, but have at it!
Or you precondition skill declarations on fictional position like DW - but empower the player to either suggest or state their skill usage once they’ve gotten to the point in the conversation it makes sense. DW says you don’t roll dice if there’s nothing at stake, because you’re resolving conflicts not tasks. 4e’s skill challenge system was also about conflict resolution not tasks res. You don’t have the system support if either DW or 4e here, but you can still adjudicate consequences that make sense in the fiction and fail forward, like the proposed bit with the owlbears.