Pumice seems simply a way to benefit from local resources ?
Is is related to what we call cellular concrete ? It is practical but have problems with water (absorbant) and safety (you can enter with a saw), but there is problems everywhere.
LENR does not benefit from pumice as I imagine, but LENR eliminate many constraints of previous system, so may allow it where usual constraints prevent it. LENR allow cheap heating, so some architecture that are today unacceptable may be practical.
On the opposite the insulation provided by Pumice or cellular concrete may not be useful... insulation anyway if not required with cheap energy is a comfort factor.
LENR introduce new freedoms, but it depends on technology maturity.
If LENR is ok for a single home, the you don't need grid around.
For heating, if LENR is dense enough it can be central heating and why not local space heating, tap boiler.
Some electricity is probably needed in the first generation that will be electrically controlled, but I imagine it will be autonomous and even generating as soon as technology improve.
This mean more freedom.
if LENR is more bulky than I imagine (because of safety or cost), then local bulky generator may be shared as an electric microgrid by a complex, with heat grid.
The design have to account for the kind of LENR maturity...
heating only, CHP or generator; noisy or silent; district scaled, home scaled, room scaled, or appliance scaled? we cannot be sure today.