Yes a 2 striper can be lined up out wide but there has to be a receiver on the outside of him and the receiver has to be on the line of scrimmage. The 2 striper must be in a 3 point or 4 point stance.
QB/RB/WR run over to their coach for play calling all the time, at most levels of play - as far as the coach being on the field that is probably going to depend on how far out on the field. A couple of steps on the field to call a play is not that big of a deal for most officials - out to the numbers and we are normally going to ask that he move back.