Why a sequel with that ending? . . Doesn't make a whole lot of sense.
As for remake. . The original was re-released a few years ago with improved lighting. If I recall Double Fine stated they had no interest to remake the entire game because the artstyle held up well and didn't want to risk altering its uniqueness.
Some games simply do not need remakes, and I agree with the creators, feel Grim Fandango didn't need one. Visually it is still a pleasing game, though could have done fixing the terrible car sections.