Anda, kamu, kau, dikau and engkau are all the same means you. but Anda is more polite and formal than others used in official forum or used for older people and honorable man, kamu and kau are general but kamu more formal than kau, engkau and dikau commonly used in poetry and song.
it used in regional jakarta dan sekitarnya only and in the other part of indonesia itu sama sekali tidak digunakan, bahkan ada beberapa daerah yang akan mengejek mu kalau kamu memakai bahasa gaul (katanya) seperti itu. coba pergi ke makassar dan gunakan bahasa seperti itu pasti kau akan ditegur "santai lalo moko ngapa saemi inne, apa nu kana injo" sebagian orang di makassar pasti akan mengatakan itu kalau mendengar seseorang menggunakan bahasa gaul di makassar.
sadly it left it's mark on many traditional media like radio, tv, movies, and social media too and because that is where many people learn conversational language it could get pretty confusing if not adressed. I've never been to makassar, and Indonesia is huge so there's always going to be cultural difference anywhere you go and that's what makes it beautiful. The problem is that there's not yet an easy online way to learn about the local,rural,and regional languages, or translate it accordingly. I don't know what you said in the quotation there but that's why it's so important for people to develop a way to learn those languages without the presence of human tutor, like the way online translator and teaching like this site is built. Thanks for your reply and being active in the discussions.