Jesus, if you knew how many times my he's best friend's halfling fought from the back of my half orc NPC, well, I guess you'd not really be surprised, but maybe slightly amused?
They also did fastball specials.
It was cheesy as hell at times, but fun
I can just imagine how terrible that bottom bar slamming into your back would feel when a child is flailing around
Not sure of intended purpose, but we used one for my son & my Hero & Baymax costumes one Halloween.
You need the same amount of head shown in the picture to allow a crossbow to squeeze into this setup.
Also note that a mounted character can travel at twice the top travel speed for an hour. It doesn't specify anything about what creature they're mounted on. And with the right feats they could be helpful. Imagine a tank with a Mounted Combatant feat riding the squishy wizard and absorbing all the attacks against them.
I don't think so. Most people have heads. That crossbow will still need room to move.
Maybe it could work if the platform were raised 6 inches.