Some of them are really dumb like Obi Wan’s teacher not being Yoda. And Leia’s mom dying before she was a little girl on Alderaan.
Other ones can be chalked up to Obi Wan lying or exaggerating or not remembering things. Like saying he never owned a droid, or that Anakin wanted Luke to have the saber when he was old enough. Or that Anakin was a great starpilot and a cunning warrior and a good friend. What was he supposed to do tell him yeah i cut off all your dad’s limbs when he went to the dark side and he is Darth Vader by the way, and your dad also killed your mom and used this saber to cut down a bunch of younglings. I’m sure Luke would have been up to joining Obi Wan on an adventure then.