Respectfully Hypr,
Kids dont need features like "bat tails" or any extra pointy bits to cause injury.
Kids on a 7' board only need 3" to 4" max thickness, any more the board becomes too corky. Short boards are actualy more stable with the tail half submeged when they are paddled, it dampens the roll & lowers C of G.
Try a board with much flatter rocker, 4" or so, & a tail with a generous spiral V. Gives more drive, particularly with an appropriate size fin.
Heaver riders 90kg or so, are still ok with 4" thickness & 31" x 8' flater decks give more confidence to run around on.