Gs scale, +engineering pay band and locality pay(if applicable). The exceptions are military, they’re paid at comparable ranks. Most civilians start around GS9, then get fed up and go contractor for better pay.
Yes. I worked in the intel space and never knew a SES who wasn't a project manager or had several direct reports. Software staff aren't SES unless they run a group. I'd be surprised if high GS numbers (i.e. 12-14) applied to software staff unless they had 10+ years of experience or direct reports.
Some of the ranges I’m seeing here are “best case too” much like “google pays 200k+”. It all boils down to negotiation and open billets / funding. SES is extremely rare even in “TAO”.