We're also a family of 6 and have gone twice since our youngest was born (she's 2 now). We stayed in an OKW 1 br villa (rented points from a DVC member I know) when she was 1. The resort was ok, wasn't particularly special IMO. The boat to Disney Springs was nice. The 1 br villa was HUGE, twice the size of AOA, but only fits 5 technically (that's another discussion entirely...). We stayed at CBR last month. It was tight but wasn't that bad. We had the youngest in a pack n play, my middle two sharing a queen and the oldest (7) in the murphy bed.
We stayed at AOA when my middle two (twins) were smaller for the bedroom. We looooove that resort but it's pricy.
For the cheapest option, I would do CBR again (or another moderate). The 1 br villas have the most space. I personally think AOA is the best balance of space and incredible theming for the little ones. Our next trip will probably be at ASMusic for costs but if AOA wasn't $100 more, we'd go back there in a heartbeat
Also, if you want to go the cheapest option, the DoubleTree Suites near Disney Springs are $150 a night for a 1 br suite. If you book via Mousesavers, you also get free continental breakfast. We haven't done that, but the biggest negatives there are not being in the Disney bubble and the buses dropping off farther away. The plus side is its walkable to Disney Springs.
Good luck!