Wood bats such as the Brett Bros. Maple/Ash Wood Baseball Bat: ST271 Adult will feature a BBCOR stamp since they are not made from one solid piece of wood.
The extended barrel design of the Brett Bros. Maple/Ash Wood Baseball Bat: ST271 Adult means this bat will have an end-loaded swing weight design. This bat will have a slightly different barrel taper as a result when compared to the MM110 and MZB331 which are balanced models.
(1) I think going for a bat like this Brett Bros. Maple/Ash Wood Baseball Bat (ST271 Adult) will be fine for a player swinging a -5 bat as it will be slightly heavier and will be good for training. (2) I do not think that a Youth wood bat would be as helpful as it can be lighter than what you have right now -and- will also have a 2 1/4" barrel diameter.