Our family functions very similarly to pp; I let my children eat dirt, rocks, sand, grass, dried cheese from behind the end table in the very corner of the room where I missed, etc... nothing poisonous though, of course.
I always laugh when my dh husband jumps in with, "Don't eat that! It's disgusting/gross/inedible!" as he rushes to 'rescue' the child from ickiness; my response to him is, "Huh. How do you know? (giggle, giggle) The funnier thing is that all three of our children always ask me if they can eat the thing they found before they do. I tell them what it is and then let them decide. Only our nearly four yr old now decides more frequently than not to put the 'thing' away and not eat it. So the other two eat lots of nondescript 'things'. I think it's fine, especially if they can outgrow the impulse around four years or so (or eight or nine, like my brother). Mind you, I did meet a man whose friend shared with me that he reflexively runs his finger along their filthy stovetop and licks his finger afterword... that's gross, but I'm not sure that it's a result of his mum letting him experiment with his sense of taste.

Or maybe it is...
Other things are strictly 'redirect' for our 16 month old. Every now and then he can take a 'no', but only if it is not a serious situation. A quick or louder than normal speaking volume 'no' scares him too, like his brothers when they were younger, and always did, which is why we don't do it, unless we do so reflexively (which does still happen). I do say no to the two older ones now, though, and they take it well. It is always accompanied by an explanation and alternative where it is possible and acceptable to dc.
And yes, op, I do think what you are doing is gd, although I'm still learning what that means in the deepest sense. I'm assuming your 'firm voice' is still gentle/loving since your redirection seems like a gentle approach.