Mending - 2xp
Unbreaking III at 4xp
featherfalling IV at 7xp
Fire Protection at 11xp (Note: Featherfalling and fire protection have same cost thus order of either does not matter)
Depth Strider III at 21xp
neither soul speed III or Thorns III can't be applied due to being "too Expensive" 
The diamond boots were new with no earlier work done on them. Normally you can put the two last enchantments on and rename the boots as shown in the other video without issue. Rather it becomes too expensive even though the previous cost was only 21xp which only a little over half of the 40xp limit.