No need to butterfly the saudis, you just need to prevent british support for them leading to the takeover of a large part of the arabian peninsula and naming it after their family.
The hashemites were moderate and well in tune with western culture as well as being traditional muslims, their problem was that they had too much influence with the rest of the muslim world and prestige for the british to stomach.
You had delegations form India, and african muslims going to mecca and begging
the sharif to take up the khalifate.
And Sharif hussien was getting a bit uppity after the end of world war 1 and he forgot that he was dependent on british goodwill for money and arms, so he had to go.
The saudis got supplies of weapons and ammo and he got nothing, and they had allot of fanatical wahabi inspired tribesmen, so he lost.
Before world war 1 the Wahabis were considered by most muslims to be some weird cult outside the fold of mainstream Islam.
As soon as the oil money started flowing by the 60's they were already exporting their interpretation of islam by building madarassas and funding the construction of mosques throughout the muslim world as well as charitable activities.
Wahabism was starting to take hold and spread form the 70's onwards, and the imagie of saudis changed to be one of benevolent and pious muslims, instead of dangerous cultists.
sadly today and growing percentage of the muslim population share the same beliefs and the wahabi or salafi interpretation of islam is becoming mainstream.