Answer
(Fatwa: 842/649=L/1430)
By not reading tasmiyah properly, if you mean that according to the Shafe?i Fiqh he left reciting bismillah intentionally, then in this case it will be unlawful for a Hanafi to consume the animal, as the Quran says:
وَلا تَأْكُلُوا مِمَّا لَمْ يُذْكَرِ اسْمُ اللَّهِ عَلَيْهِ وَإِنَّهُ لَفِسْقٌ
?Eat not of (meats) on which Allah’s name has not been pronounced: that would be impiety.? (6:121)
(2) If he goes to church and stands under cross in reverence, it is haram, rather he fears to fall in infidelity. He should repent to Allah and seek His forgiveness. Out of caution, he should renew his iman (faith) and Nikah.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband