Vapor barrier, insulation & ventilation considerations?

[Almost0.5acres]

The initial plan was to attach the vapor barrier to the rafters with 195 mm insulation between the rafters.
Have an HRV unit between the intermediate floor and the rafters.
The HRV unit doesn't fit there (must have planned wrong) and it becomes a real hassle/taping to get the vapor barrier past the intermediate floor (planned wrong).

So...

Can I have the vapor barrier as in the picture with insulated intermediate floor beams (170mm insulation) and insulate rafters (195mm insulation) with ventilation ducts running in between without risk of moisture problems? Can you seal around the exhaust (ceiling) and supply vent (wall), so they don't create any problems?

The wall-mounted HRV unit can hang in the bathroom/laundry room.

What type of fabric can I stretch between the rafters to keep the insulation in place or should I use lath 28*70 with cc 45 (will not use gypsum or similar).

Poor image explanation:
From left to right
Vapor barrier outer wall --> vapor barrier under the intermediate floor --> up tightly via the partition wall --> via the rafters to the right outer wall.

 

[Almost0.5acres]

This is how it looks right now. The support line runs along the entire heart wall. It would have been convenient to have the vapor barrier on the underside of the intermediate floor.