Is it permissible to use simplified methods in the religious upbringing of children, such as linking mistakes to a lack of love for Allah and the Prophet, interpreting verses in a way that suits their age, and facilitating the memorization of the Qur'an and Sunnah by changing some words?

It is impermissible to replace the words of the Holy Quran with other synonymous or opposing words in meaning. Although what the questioner is doing is not a complete نقل (transmission) of the Quran in its full sense, it is not without issue. Therefore, this method should be avoided when teaching the Quran and Hadith. There is no objection to using gestures to convey meaning or uttering a letter from the word for reminder, provided that it does not involve altering the لفظ (wording).