Remember when people were pissed that Diego Luna wasn’t playing Biggs, because he has a mustache?
If you take the deleted scenes from Star Wars as canon (I do), then Biggs only joined the Rebels about a week before Luke got to Yavin. Wouldn’t make any sense to have Biggs involved in that story.
Just FYI;
According to the old EU, and I do believe it was implied in the radio play as well (which was “Lucas canon”), Biggs had actually joined the rebellion months before the deleted scene at Tosche station. Him returning to Tatooine and telling Luke half-truths (he had already gone to Bestine) was two-fold; to “recruit” Luke to the rebellion as well as creating a sort-of alibi should he be arrested.
Either way it’s a nice little head-canon possibility. It is for me anyway.