I don't think the timeline makes sense.
In theory Dolores went all Wyatt just before opening the park, causing so much damage to the hosts (and designer team) that they only could open thanks to a benefactor who bankrolled them. That's supposed to be William/Man in Black.
However, William/MIB would only have had the disposition and resources to bankroll the park after some time. And he only went for the first time at the behest of his soon-to-be brother in law, who had already gone many times himself (he was quite familiar with what quests would be too vanilla/boring for him).
Am I missing something?