Yea I wondered about that "breathing hard". At VT1 I can still chat comfortable and easy. Even above VT1. You're using a different definition.
By your definition, everything you have written is correct and I agree completely.
As defined in the literature your definitions basically OBLA/VT2. VT1 is 2mmol lactate. Most people can speak complete sentences up to 4-5mmol lactate or about HMP.
It's just a definition thing. The scientific literature is clear. I've now found over a dozen separate studies, many of which I have linked showing VT1 to be well below threshold, not almost the same.
By the literature definition, nobody is breathing hard at VT1, at 2mmol, at 75% HRmax, or however way its commonly defined (2mmol lactate being most common literature definition). Elite marathoners run closer to 3mmol of lactate, well above VT1.