In regards to youngsters ability. Has FFG made a statement?
Is the TIE/sf a TIE fighter?
Yes.
They don't need to make a statement. Rules make it clear that if it says 'TIE Fighter ' in the ships name it's a TIE fighter.
So TIE/FO and TIE/SF are TIE fighters.
Ref: page 20 of the rules reference "Ship Type Only"
Edited by Stu35The FAQ entry for Youngster already says his ability works with TIE/FO fighters. Why would TIE/SF Fighters be any different? (Don't answer that. They would not.)