The late Denny Miller, one of the Tarzans of the Cineverse, made two appearances on 'Gilligan's Island'. In Season One he played surfer Duke Williams, who rode a wave for five days and then landed on the island. Later he returned to the show as an actor who planned on using his experiences on the island for his screen test to play the lead in "Tongo the Ape Man".
We never learned the real name of that actor; the castaways only knew him as "Tongo". So why can't we tidy things up by claiming that Duke and "Tongo" were one and the same?
The fact that those seven stranded castaways didn't see the resemblance between Duke and "Tongo" was already a Zonk that needed splainin. Since I planned to disable that discrepancy anyway, why not take it that further step?
Duke Williams gained a lot of publicity from his marathon surfing (although he never mentioned the castaways once he got back.) I think it might be reasonable to assume that he would cash in on that notoriety with book deals, public appearances, and yes, even a movie role or two. He wouldn't be the first from that time period to capitalize on their fame in other fields by acting in the movies. Mel Torme, Roy Orbison, the Beatles, and even farther back, Audie Murphy.
And Duke Williams already knew the location of the island, so he probably saw it as the perfect site to stage his "audition".
But why didn't Gilligan and "all the rest" recognize the fact that "Tongo" was Duke Williams?
The Island from 'Lost' was not the only island in Toobworld with mysterious energies. So many of the "identical cousins" of the castaways were drawn to that island; it seemed to affect satellites and space capsules so that they would crash on its shores; and plants unknown anywhere else on the planet seemed to thrive there.
One of these plants was the bush of "thinkberries" which gave people the ability to read the minds of others. (Dried berries from this bush make an appearance in my Toobworld novel.) So why couldn't there also be a bush of berries, or perhaps a new strain of vegetable or mushroom which when ingested would cause amnesia?
When you consider plotlines about mind transference along with visits by rock bands, military dicators, and Japanese soldiers who think WWII was still going on, would such an amnesia-inducing food be so far-fetched?
In a never-seen adventure of the show just before the arrival of "Tongo", the castaways may have ingested such a food which gave them selective amnesia about the identiy of Duke Williams.
With 'Gilligan's Island' being so unabashedly silly in their suspension of disbelief, I think this is a fairly reasonable splainin.....
But even if you hold fast to the belief that Duke and "Tongo" were two separate characters, I would hope you would at least entertain this theory of relateeveety - that both men were descended from a 'Wagon Train' scout named Duke Shannon. (As far as I'm concerned, Duke Williams carried that name in memory of his grandfather.)
Submitted for your approval in memory of Denny Miller.
Good night and may God bless......