There is no need for an alternative hypothesis. The burden of proof rests solely on Smollett. No other hypothesis is needed, to observe that Smollett has not met his burden of proof. No other hypothesis is needed, to observe that Smollett has actually refused to do things that would provide even the most minimal amount of corroboration.
At this point, we can simply and reasonably say that while we do not know what really happened, there is no evidence that it happened the way Smollett says it did.
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ETA: That being said, my alternative hypothesis is that a unicorn tried to gore him, but because Smollett is still a virgin, the magical beast's horn glanced off his chest, leaving him with a cracked rib. Since "this is MAGA country!" is marginally more plausible than "a unicorn mistook me for a fallen woman", that's the story he told to Jake the Condo Guy. Totally understandable, but what a tangled web we weave, etc.