That would actually be pretty cool. But it would need to do Continuum without any additional hardware being needed, except a cable. Kind of like what Samsung Dex does.
should not be that hard to implement on android. android supports video out & mouse input. all Microsoft need to do is provide desktop style environment & windowed multitasking support.
also make sure that both continuum screen & phone works independently as well when connected.
They would have to emulate Windows 10 or adding a Windows runtime.