The EJ205 has 92mm pistons, but uses an odd sized 23mm wrist pin. After scouring various parts of the internet, it looks like Mitsubishi 6G72 pistons may be pretty close to fitting.
The 6G72 uses 92mm bore pistons with 22mm pins, a compression height of 32mm, a -14cc dome (Wiseco) and a 48cc combustion chamber.
The 3MZ uses 92mm bore pistons with 22mm pins, a compression height of 31.2mm, a -1.7cc dome and a 56.3cc combustion chamber.
According to Victory Library, to bring the 3MZ down to 9:1 compression, you need to add an additional 12.67cc to the combustion chamber (68.97cc). Using the 6G72 pistons -14cc dome and 0.8mm higher compression height will put the combustion chamber at ~65cc, setting the compression ratio at ~9.5:1, pretty much the place I want to be if I'm adding some boost to it. A slightly thicker head gasket might be useable to bring the compression down to as low as 9:1 if t's really needed.
Another bonus is that the 22R rod has the same small end width as the 6G72 pistons, so it will only require machining of the big end width down to 16mm to suit the 3MZ crank.