Grand Funk Railroad
Fletch-Still Alive 
I'm possibly the first French-speaking Nurse Anesthetist who can play all instruments on Expert
All RBN songs have that, don't they?
[X]TLoZ [ ]TAoL [X]ALttP [X]LA [X]OoT [X]MM [X]OoS [ ]OoA [X]FS [X]TWW
[ ]FSA [ ]TMC [X]TP [X]PH [ ]ST [X]SS
Yes. All RBN songs have the SR badge.
Kario Charts - Charting Uncharted Territory
Even if they were family friendly they wouldn't be playable in Lego.
 Dizzy Mizz Lizzy  Dover  Guano Apes  More Miley Cyrus
 The Rasmus  The Veronicas  More Volbeat
It's an extra step that Harmonix doesn't really have the manpower to dedicate to. Same reason why they don't check songs themselves after they pass peer review; the approval process is automated.
It also helps that all RBN songs are placed in the RB2 folder on the HDD. LEGO is likely coded to not look there for songs which makes it even easier to avoid any hassles. (RB1 also cannot see them, and you'd hardly think it needed to know about 'family friendly' crap.)