2. 1 Cor 16:2 - Paul requested the special donation for Jerusalem should be made by saving the money at HOME on the first day of the week, he didn't ask them to come to the church on Sundays.
3. Acts 20:7 the first day of the week, evening meant the Saturday night, next day, on Sunday, Paul departed for Journey. Bread-taking was done very often in the Early Church ( Acts 2:46). In acts 20:7, they might have celebrated the early bread-taking in the morning, then in the evening, for the slaves who couldn't participate in the morning service, they had another bread-taking plus Habdala which was a house-warming party at a private house.