Re-entry Rule

Yes, he can re-enter in the same spot in the line-up, just like any other player.

Are you also asking if he can return to the mound?

No just if he was able to re-enter the game. But that is a good question could he return to the mound?

Yes, one time per inning, provided none of the rules governing pitching/substitutions were violated.

I haven't seen this situation come up in a long time, but it used to be my understanding that if a starting pitcher was taken off the mound but remained in the game at another position, he could be put back on the mound once during that game. However, if he was removed from the game completely, he could reenter, but he could not pitch again. Is that not still the case?

Not in HS. There other leagues that allow reentry that this not true. In HS he can leave the field and return to the mound.