按照你4#的要求, 加入lunar year holidays 有些牽強, 因件事發生了一段時間, 你無可能話john在整個假期不斷和弟弟在玩玩具, 有些不通順. 正如我之前給你的例句, past continue tense 要配合something happened at the same time or almost at the same time
如果一定要用past continue tense, 我會suggest:
John was playing toys with his brother during the lunar new year holidays.
但我會覺得past tense + suitable preposition 會好一點:
eg. John played toys with his brother in the lunal new year holidays.