Also, question about that big 470uf capacitor on the BATT line at C16 on the Betz board. If we're not using an actual battery, and instead supplying 3v directly to the chip, we don't need a big cap in that position at all, right?

The battery charger is designed to operate with a permanently connected battery. If the application permits the charger input to be connected while the battery is disconnected, the VDD_BAT pin voltage may become unstable. This, in turn, may cause damage to the internal switch-mode regulator. Connecting a 470uF capacitor to VDD_BAT limits these oscillations thus preventing damage.