There are no combos in this game out of a grab release, except for Marth/Lucina
aerial grab releasing into custom Up-b 2.
www.smashboards.com/threads/grab-release-mega-thread-spoilers-almost-zero-combos.373720/
So no. Grab release to Jab is by no means a thing. The opponent can either shield or use a faster attack, which isn't difficult seeing as Toon's Jab is a dismal frame 6 move. To make this point clearer, in a grounded grab release both you and the opponent can act at the same time; shield is active on frame 1, and if the opponent's character has a move that hits earlier than frame 6 that reaches you (most characters do), trying to Jab them predictably every time will just get you punished.
Oh and I should note, concerning the vid, jumping towards the opponent and pulling a bomb
in the neutral is a bad habit. Also it's very difficult to tell how good a player is or where they need to improve by looking at a highlight vid. Uploading a whole match (or better still, a whole set) against a player who is better than you is what's best if you're after critique.