Imagine if they don't include the DLC? That would be super funny.
Earlier posts more or less sum this up well, but I think now that we're a bit deeper into COVID and know how its affecting the games industry in particular, projects like this make more and more sense. Who knows what the dev pipeline actually looks like, but there's probably very little new development needed to get this stuff up and running given backwards compat. was already in place (IIRC.) Outside of that it's just artists doing their thing, I assume.
I just stumbled upon a 360 copy of ME1 today and will probably tear through it again just for fun.