Mac is a character of extremes--Very weak aerial mobility but incredible ground speed and positioning. Three of his aerials seem borderline useless in the neutral position, but maybe the angles they send at could be of note in specific positions. N-Air and D-Air definitely seem like they have potential.
N-Air is a very quick jab at a 45-degree angle forward and down with something like 15 frames of animation altogether. Doesn't seem to have much knockback, but I could see it setting up for other moves, like a stronger aerial or a grab. N-Air -> footstool will probably be a reliable thing!
D-Air hits straight down and doing it immediately out of a shorthop makes it finish before landing. With his good runjump speed, I could see it being useful as a safe poke that could be set up on. Going into neutral before landing in that probably means that run-jump D-Air -> B-Reversed specials (B-Reversing is confirmed, as an aside) would be a solid hit-confirm, which should combo into his KO Punch.
Ground speed is great and dash/run is very low to the ground (think a faster Sheik). He has a walljump, too, which is neat and could be important for recovery purposes.
I didn't get well-acquainted enough with the Pro Controller to try Jab -> Grab stuff. Rapid Jab seems good in 1v1 but takes a while otherwise. F-Tilt is a quick, safe one-two that should be solid for spacing. U-Tilt seems like a good combo option, kind of Fox-ish. D-Tilt is slow but has good range and might pop up well for follow-ups.
U-Smash has GREAT speed with reasonable KO potential. With super armor on top of all that, this will probably be his go-to option for all sorts of stuff. F-Smash has solid range and is more powerful; could be a good counter-poke with the armor. D-Smash swings around quickly and has solid range, too.
B-Throw has solid power; should set up for potential edgeguarding well. One of his throws (U-Throw, I think?) has low knockback and pops them up in front of you. I expect it to trap people really well with a potential super-armor attack like running U-Smash.
Forward-B appears to have a Smash and Tilt version of it, which is better for recovery than one might initially suggest. Up-B is garbage for recovery. I couldn't tell how powerful Down-B (CROSS COUNTER) was.