Mimimum requirements for a perfect emulation

You don't need to overclock it. But if you're getting the 8700, might as well go the extra mile and go for +500/1000MHz and get that extra performance. You can just get the 8700 and call it a day too.

TSX is not mandatory, but helps performance when present.

I already said above, you shouldn't be comparing 2600X with 8700, it's R7 2700X vs i7 8700/8700K and the i7 wins easily in RPCS3.