>>43185454The trade in Home is completely non-functional and I doubt it's born from good intentions. It's completely within Nintendo's capabilities to make exceptions for NSO (and they have in the past!), if pokémon trades and battles require a subscription, it's because none of the parts were very interested on avoiding that.
As for Virtual Console, that's just a brand... that is completely dead, they don't and won't use it anymore. What they have going on now isn't a "subscription virtual console", but rather NSO services among which are NES games and SNES games (but not Game Boy, Nintendo 64, Game Boy Advance, Nintengo DS, Turbo Grafx, or Game Gear).
If they want to release Game Boy [Advance] Pokémon games they absolutely can, they just need to call it something that isn't "Virtual Console". SNK has come up with "Arcade Archives", for instance. "Game Boy Memories", "Pokémon Classics"... they can do anything, as long as it doens't directly itnerfere with their current "service" or any projections they have for them.
They might be holding GB Pokémon games hostage for the eventuality of a "Game Boy - Nintendo Switch Online" app, but if there's any interest from Game Freak or Nintendo to do it differently and it seems more profitable than not doing it, they will absolutely do. There is no technical limitation or higher authority that can stop them.