Do Weirdboys use the errata of the Freebooter stats in Into the Storm or their remain the same?

And do they gain Insanities or not?

And why they have differents skills and talents for klans?

I would use the characteristics in Navis Primer for their stats, since the errata doesn't say otherwise. I would treat the mention of Madboyz as referring to what it is for a Freebooter: They get Insanity Points, but no one notices until 100 at which point the Weirdboy breaks.

They have different talents for Klans because the book came out later. The Navis Primer came out after Into the Storm, so all else being equal I would defer to it for rules about Orks.

Dey's different 'cause dey iz Weirdboyz, an' da otha ones iz Freebootaz.

Use what's in Navis Primer for them, unless Navis Primer has anything related to them in its errata. Into the Storm generally doesn't apply except for the orky alternate ranks for your Weirdboy, as well as orky gear. As Into the Storm came first, and its errata came before Navis Primer, if it didn't make its way into the Navis Primer, then it was probably felt it didn't need to be there.

As far as insanity goes, it would appear that Weirdboyz do gain insanity, and various mental disorders, as per normal (unlike Freebooters, who just become unplayable at 100 insanity). This is how it reads to me, and there is nothing there that reads otherwise. FF could have forgotten the last three sentences from the Freebooter description, but then, maybe not. Given that Weirdboyz are, well....weird... I'd just say use whichever rule you feel like, either gaining disorders and hamming them up in RP, or not, like regular orks. Your call there.