Interesting...
Hashemite Hejaz. Haven't seen that before. I've seen TLs where the whole of Arabia becomes Hashemite or Rashidi rather than Saudi, but not the Hejaz being separate.
Oman as a protectorate of the Indian Empire?
Between the Treaty of Versailles and the final unification of Arabia by Malik Abdulaziz ibn Saud in 1932, there did exist a Kingdom of Hejaz which was ruled by the historic Hashemites of Mecca (who only in OTL became Jordanian kings because the Saudis defeated them) while the center and east of the penninsula was ruled by the Sauds as the Kingdom of Nejd.
de facto of the Indian Empire, which technically would have been a compromise to be neither British nor French.