Chandra broke the SAL computer back on Earth when he tested her logic circuits.
That's why he almost angrily says to Hal that he doesn't know if he'll dream. He could have simply said SAL did or did not dream, but instead was reminded of the mess he made.Hal was toying with the crew of the Leonov when questioning Chandra during their escape from Jupiter.
As the one to control the Discovery during the procedure, Hal knew the date they needed to leave and how it was to be accomplished. From this, it would be easy to see the Discovery would not be able to return to Earth, so why did Hal hold off asking about it? Because he wanted to mess around with the crew, that's why.- That's not necessarily true. It would have taken longer, perhaps too long for a human crew to survive even if they went into hibernation (and no human would probably want to trust Discovery's hibernation equipment anyway), but Discovery could have made it back to Earth if Jupiter hadn't exploded. The crew didn't know for certain that Jupiter was going to explode, but they suspected that Bowman was warning them to leave because both ships would be destroyed if they didn't.
2010's production team only had a 35mm print of 2001 to use as reference.
2010's attempts at reconstructing the Discovery sets had some mistakes that could only have been made if the reference material wasn't high resolution enough to capture all the details. For example, in 2010, the speaker grilles under HAL's camera eyes are blank gray rectangles, instead of being horizontally corrugated and perforated with holes like they were in 2001. The black parts of the pod bay floor are highly polished, instead of being carpeted surfaces intended to stick to Velcro boots. This suggests that the production crew was referring to a 35mm print of 2001 instead of a full 70mm print.