Most of the PS team working on the hardware were from the electronics team. Some of them were even former employees working of Nintendo, Sega, and Toshiba.No. Sony Music Entertainment Japan created Sony Computer Entertainment Inc. in 1993. Many years later SCE got renamed to SIE.
Sony Music has two parts that operate independently and make separate reports to Sony's investors:
Each one of these branches have many subsidiary companies, most of them bought or merged. In the case of SME it has dozens of country specific subsidiaries, one of them being Sony Music UK (also known as Sony Music Entertainment UK) to record and promote artists from UK. Just to name another examples, there's also Sony Music España/Sony Music Spain, Sony Music Poland, Sony Music Australia, etc.
- Sony Music Group (SMG), which handles their music business outside Japan, in the rest of the world, from USA. It's split into two halfs:
- Sony Music Entertainment (SME), also known as Sony Music, which is their recording division
- Sony Music Publishing is their publishing division
- Sony Music Entertainment Japan (also known as SMEJ or Sony Music Japan), which operates their Japanese music business in Japan, anime and some Japan focused videogames
SMJE are just there to lisence and redistribute.
Think of it as a distributor and a workhouse.