Thanks. That helps...I think.

(Why in Heaven's name does United use such a jumble of terms that can only cause confusion, and confusion gives rise to customer unhappiness?!)

If I buy Basic Economy on a domestic flight, my Gold status may or may not get me an E+ seat, depending on whether there are any E+ seats left unsold, so don't count on it? Are there priority lists like the ones for "upgrades"? Arrival time at the gate might determine where I wind up sitting?

Does Basic Economy exist on UA international flights or just on domestic ones?

"Refundable" is different from "change fee"? The first meaning you can get your money back; the second meaning you can change flights without fee unless the fare has changed?