An important thing to remember about the read a sitch and read a person moves is that their triggers are specifically for charged situations or interactions. These are not "perception checks," but rather moves that are used when there is obvious tension, danger, peril, or conflict. If the player simply wants information about their surroundings, just tell them.
As for how you convey information, it really depends on the situation. So for who's really in charge here? you might say something like, "Rolfball is puffed up and talking a lot of trash, but you catch him glancing at TumTum every so often. You get the impression he's looking for her approval." Or for what is this character really feeling?, you can call attention to subtle cues or tells. "Yeah, Rolfball is yelling and gesturing like a raging bull, but there's a little quaver in his voice. You think this apparent anger is a display to cover his fear."
Also, don't be afraid to alter/add to the in-game fiction when answering these questions. When a PC asks, which enemy is most vulnerable to me?, it's time for you to invent an exploitable vulnerability on the spot. Say there are dudes from Dremmer's gang on a cat-walk, an elevated position that will deprive the players of any cover. But hey, as soon as the player asks, that cat-walk is supported by a single rusty beam - break that and all of those dudes are coming down ass-over-teakettle. When the player says, what's my best way in, that's when you invent a way in - "As you pick your way around the perimeter keeping out of sight of the sentries, you see a Rad-Rat dart out of an old, mostly-blocked drainage tunnel. After moving some rubble aside, you can see it's tight quarters and gods only know what's down there, but it looks like it leads straight into the complex - that Rad-Rat looked pretty well-fed."
In MC parlance, these are chances to present an opportunity, with or without a cost.