Hey LostOverThere! Hope you are well.
I believe that Welles was only supposed to write and star in TREASURE ISLAND, although Frank Brady reports that Welles was originally slated to direct. Jess Franco, one of Welles's Spanish assistants on CHIMES, ultimately assumed the director's role; whether this was intended from the outset, or due to the vagaries of Spanish production, or because Welles was absorbed by CHIMES, or by default, remains an open question. The now notorious Franco, then early in his incredibly prolific and controversial career, had recently directed DEATH WHISTLES THE BLUES, a stylish, low-budget homage to TOUCH OF EVIL that Welles had seen and admired. Pre-production on TREASURE occurred simultaneously with the production of CHIMES. According to Robert David Monell, who has interviewed Franco extensively, a nervous and wary Franco asked "that if just acting (in TREASURE...) was going to be any different than if he (Welles) were directing himself. Welles answered, "It's the same..." and went on to tell Franco that he would be the creative force and to do as he was told."
That Wikipedia article sure is odd. It claims that Welles never intended to shoot TREASURE, and never wrote the script, but I'm not sure I believe that. Welles was vague about his plans for TREASURE, and the impetus was surely to gain financing for his beloved CHIMES, but a script did exist, used later for the ill-fated 1972 production, and TREASURE was something of a pet project for Welles, according to Brady. Juan Cobos, who worked closely with Welles on his great cinematic obsession, DON QUIXOTE, mentions TREASURE in one of his articles, and I think Welles may have conceived TREASURE as the great commercial project that would allow him to release the highly experimental DQ without critical opprobrium. Leveraging TREASURE to acquire the financing for CHIMES, and then piggybacking the release of DQ on the back of TREASURE's (hopeful) commercial success, would have been an awesome one-two punch for the so-called has been.
It was not to be. Although Brady writes that Saltzman came in early, most sources insist that the Bond producer was late to the party, purchasing worldwide rights after Piedras had nearly gone broke, with the proviso that Welles stop editing and hand over the film for distribution. Evidently, Franco had some part in this deal, which so infuriated Welles that he physically attacked the Spaniard, before shutting him out of his life forever. This is the event, I believe, that demolished TREASURE ISLAND, the pieces of which were only picked up, very haphazardly, by Harry Allan Towers (who produced both Welles and Franco at various points in his interesting career) in 1972.