1. When using Force Points, the comstar advantage and clan invasion are already factored into their costs. ComStar would not get double, and the Clans would not get another free skill boost. When using BV or PV, you can either not use BSPs and not give Clans a free skill boost (ComStar can buy artillery, aerosapce units, etc and the Clans can pay for their higher skills, or ComStar can buy higher skills/more units and not get artillery/aero/etc and vice versa), or you choose the option to give ComStar free BSPs as shown on the table and give the Clans a free skill upgrade. But you would not give ComStar free BSPs twice.
2. No, there are no BSP to BV conversions that I'm aware of. The BattleMech Manual has the full BSP rules and has recommended amounts to give to each size, but it's not a BSPs cost this much BV and generally assumes both sides get the same number of BSPs.