"You have cats."
Translation:Kamu punya kucing.
Ummm this is kinda hard.. while "ada" also means "have," it isn't really used outside daily conversations. Meaning that it's not really a word that you should use to write formal letter, formal meeting, etc.
"Ada" also means "available." So basically "kamu ada kucing" while you can translate it as "you have cat(s)," you can as well translate it as "you have cat(s) right now." If I'm a translator (I'm not), I'd choose the latter since it's more contextual in that sense. Also yes, "ada" is used as an informal word of "punya" in Greater Jakarta as well.