Yes, but BA elites get priority. The BA board likes to pretend that any BA elite takes priority over any OW elite, but that is not true, the actual priority followed most of the time by BA (and their official policy) is the following sequence: BA Premier, BA Gold, OW Emerald, BA Silver, OW Sapphire. But most BA elites never travel in WT+ so you won't be competing with many of them for upgrades. BA elites that do travel in WT+ aren't elite the following year (BA status earning is quite different than on AA).