Even if control of the targeted monster shifts to your opponent, it is your opponent who takes no Battle Damage this turn from battles involving the targeted monster.
The target of “Miracle Locus” can attack up to 2 monsters, or can attack directly. It cannot attack a monster and then also attack directly.
You can combine “Miracle Locus” with “Double Attack” and the monster can attack twice. In which case it could attack 2 monsters, or it could attack a monster and then attack directly, all with the +1000 ATK gain. However, your opponent would take no Battle Damage because of “Miracle Lotus’” [sic] effect.
You can target monsters with “Miracle Locus” that could otherwise attack multiple times (in order to give them the ATK boost).