Nope, giving units ghost will remove their collision from other units towards them.
Which is indeed something that had to be done... but not for actual walking.
It is only for pathfinding and with this, the units could literally walk through the other units.
When making all units classified as "walkable", your pathfinding thinks that it is walkable but when that rider comes to that infantry, it will still be blocked.
The only thing that now changes is the pathfinding route and that was the theoretical solution which just had to be found in the editors.