The girls on either side of Kelly...are they Brandon's daughters?
No.  One, if not both (not sure on the dark haired gal), are Ronnie Dunn's kids.

in that "family" picture, besides Reba, Narvel, Kelly and Brandon, there's Ronnie Dunn (+family), Lee Ann Womack (next to Reba) and her husband Frank Liddell (+family).  No clue who the group directly behind Kelly and Brandon are, nor do I really care.  lol