Your ERD is NOT 622mm.
622mm is the BSD, Bead Seat Diameter, an entirely different beast.
Don't think you have 48mm hub flange either. That sounds like derailer gear/front rim brake hub dimensions.
And while not impossible, IMO it's unlikely that your hub will be that symmetrical. All IGHs and coaster brake hubs I've dealt with have had SOME offset, resulting in a 8-10% difference in spoke tension balance for a properly dished/centered wheel.
The difference won't be big, but might be big enough to influence decisions about rounding up/down spoke lengths.
Hub spoke hole is unlikely to be 2.0 mm too. Most spokes are 2.0 mm at the bend. It'd be a struggle to force a 2.0 bent spoke through a 2.0 hole. Most spoke holes are bigger with 2.3mm the measurement I recall.
There are spokes that are 1.8mm throughout. I suppose those might be a snug fit for a 2.0 mm hole