My opinion:
.Forget the 6502, Z80... emulation for the next version
.Develop one composite video generator as good as we can using an 8052...why? Because we can! all we know that is easier using an vga, xga card or a silicon graphics station ... but this is a game to do all we can do. (i think)
.Other(s) '52 could do the rest.

At the start the sound will be a simple beeper (not an stereo 44KHz 16 bits system)

The keyboard interface was discused a lot of times in the forum..

The Ide interface seems is done

...