So Here's my thought (Based on the names in the OP list) :
Team John :
TBA (Samara?) = I'd say Janora Brown because of their not-so-similar names.
TBA (Joshua) = Zero clue about him
TBA (Kayla? Possibly Keilah Grace) = Keilah Grace
TBA (female, "D" name) = No clue
Team Ariana :
TBA (female; possibly a "K" name vs. Bella) = 80% Kaitlyn Velez , 20% Katie Mortimer (I believe its Katelyn though)
Team Blake :
TBA (brunette girl, saved in battle vs. Hailey Green) : Lexi Stojack wasn't 100% sure BUT I REALLY do hope its her I just can't see the coaches did not turned their chairs (at least one chair) for her and she's the only brunette girl so far.
TBA (female, white) : Lana Scott (she was in the hotel during the battles)
TBA (male rocker) : I've been sleeping on Jeff Martinez if the source mentioned "middle-aged male, long hair, rock" he's the only one from the unconfirmed male list that fits the qualifications (at least for me)