A few other suggestions:
First, with the chord fingerings you originally gave, instead of lifting your fingers completely up, just release pressure, drag them laterally across the fingerboard to the next strings till you feel each finger make contact (and then a tad more, so the fingers center more on the strings), then press down. Do it slowly at first till you get the feel, then gradually speed up. I suspect your fingers do inconsistent things because you're not minimizing what they have to do. Easy playing is efficient: the least pressure needed, the least movement needed. If you do a mostly lateral movement, your fingers won't have an opportunity to get disoriented. Also aim at staying relaxed—one of the greatest values in practicing slowly is that it lets you pay attention to how much movement, effort, pressure, hand tension you're instinctively (and wrongly) using.
practicing this.
Second, if you use the B7 barre form (2322), try this: for the Em chord shift the barre and middle finger laterally one string, adding the ring finger (0432 with the index forming a 3-string partial barre 0222), instead of drawing the index all the way back to the 1st string. Why? To form C you need only shift laterally one string more to play the 1st string 3rd fret with your middle finger (keeping your barre finger poised in the air close to the strings). To play the following G, move the middle finger back to the fret it previously left (2nd string 3rd fret) and drop your 3-string barre back down behind it. This alternative fingering conserves motion and hand shape. Your pinkie (unused in all this) may start sticking out in the air; don't let it! Keep it arched and down close to the strings like your other fingers
working on this
Third, for the Em try 4432 rather than 0432. Leave your ring finger on the 4th string, reposition your index and middle fingers as before, and plant the pinkie behind your middle finger on the 3rd string. This gives you an anchor point. Though more complicated, you might find it easier to do because of the anchor point.