Tattoos are haram in all forms, whether they cause pain or not. Tattooing involves changing the creation of Allah. Prophet Muhammad cursed the one who does tattoos and the one for whom that is done.

1- The correct view is that adhan is fard kifayah (a communal obligation); if someone who is competent does it, the rest are absolved of sin. 2- If a person starts to pray without the adhan or iqamah, whether out of forgetfulness or ignorance, or for some other reason, the prayer is still valid. 3- If a muadhdhin gives the adhan in one neighborhood and all the residents can hear it, that is sufficient. For more, see the detailed answer.