> OK if we started with MOS 1.x

The actual negotiations to make MorphOS the next AmigaOS took place in 2001 during MorphOS 0.4 to 0.8 era even. But as we know, they failed.

> MOS Emu and OS4 Emu could be possible IF teams worked toughether

OS4Emu was even possible without the consent of Hyperion, who resorted to have their SDK inject anti-OS4Emu code into compiled OS4 programs without the knowledge of the programs' authors. So working together is not necessarily required, but forgoing stupid prevention measures is.