Kind of a loaded question but I'll try unpack it for you.
It depends on the character, sort of.
The characters you mentioned (except for mac, not sure why you mentioned mac) were designed to be able to do this, so they were given training wheels so to speak which gives them more time to make the B-reversal input and also makes it so they cannot B-reverse before they hit in front of them. See normally with other characters you can input a B-reverse for an U-special on frames 2 to 4 and have it B-reverse on frame 4, but with these characters it's impossible to B-reverse any sooner than the frame following their first active hitbox (which for some happens to be frame 4 anyway). This is most easily notable with the likes of Luigi. (Incidentally, it seems the same was planned for Ryu, but at some point they must have made Shoryuken one frame slower, so while he has the same mechanics as the characters mentioned, he doesn't get this specific benefit.)
Note that with all B-reversals, you need to be holding the joystick in the opposite direction on the frame you are able to B-reverse. While this won't be notable with most characters (e.g. you'd have to hit backwards on frames 2-3 then return the joystick to neutral by frame 4 to have it screw up), this can be more relevant for the likes of Luigi or any of the training wheel characters if you actually hit the opponent and have to wait out the hitlag before you can B-reverse.
If you're using any character other than the ones with training wheels (unless there's some other character specific thing I'm unaware of), you can in fact turn around without needing to do a B-reversal, and you'd do this by simply holding the joystick up/diagonally-up and hitting special, and this will directly turn you around on the first frame that the Up-special was used (and you can then B-reverse out of that if you wanted, provided you're quick enough). If you try to do this with the training wheel characters, they will not turn around as they are unable to do this. If you continue to hold the joystick in the same direction, they will instead do a B-reversal as soon as they are able to.
I hope that answers your question.