In practice the terms overlap heavily. "Standby" describes how the unit operates (automatically, always connected); "whole-house" usually describes sizing (enough capacity to run the entire home rather than just a few circuits).

Roughly, yes — cost tends to scale with kW capacity, though pricing isn't perfectly linear across every model and brand.

Not always — some quotes bundle it in, others list it as a separate line item, so it's worth asking explicitly when comparing proposals.

Yes — placement needs to account for local drainage and flood-prone areas identified by the city or county, in addition to standard manufacturer clearance requirements. An installer familiar with the area will factor this into the site assessment.