Link can't glide toss. I did try very hard. You can throw items out of a shield, you know? Well in a glide toss you go into your roll and at the start you can actually still throw an item, even for link. Like, you can begin the rolling animation and then throw a bomb and you'll stop your roll. Reason why link doesn't appear to have any gliding component though is because once he starts moving, he's in an actual roll where his feet are off the ground. The other glide tosses that actually have movement all involve the character actually moving distance on their feet when they cancel out of their roll with the toss, which is where they get their momentum.
You can start a roll and before link does the whole "rolling" thing he can still throw his bombs and cancel his roll. He just doesn't have any momentum yet at that point. The same sort of things happens to Zero Suit Samus's backwards roll- she can't glide toss with it, only her forward roll. Check it out slowed down in training mode yourself if you'd like.