Visa Application For Family Members

Hi, I'm Samantha from Ipoh. I'll be going to China this coming March for family vacation. We'll be traveling in a group of 7 person, touching down in Guangzhou for 4 days & proceed to Macau for 3 days before flying off back to Malaysia. What kind of entry permit should we apply (Tourist L single entry, double entry or multiple entry)? Is it possible for us to appoint my sister who's in KL (she'll be traveling with us in the group) to do the application for us? If yes, do we need to prepare an authorization & imdenity letter for her to collect the visa on behalf of us? Besides, will it be better if we do visa application through online? Please advise. Thanks 😊