Khaikaa

if that happens even changing layers may be a problem of the tilesets, are they in png format and with empty background?(0 alpha)

Also you can use the selection tool to select a whole map, use the copy tool, go to the new map and use the paste tool, that's the way I do it and you only need a few seconds for map. The copy tool is powerfull, it gets also the map atributes and else, so you won't need to add all these block atribute squares and else.

By default intersect sets a drop percentage that makes players losing random items from their inventory. You can change that in the server config.xml file.

I think that feature is hardcoded, we can't manipulate it with other types of equipment.

So easy to do, but buggy
 
You can create a spell which costs negative health and do the same amount of true damage to an enemy. The bad point is that you can surpass your maximum health doing that.

Yes, you can manage that in many ways. For example, you can do one class for each race x class or you can manage that using variables: you can create the player variable "playerClass" where 0 = human, 1 = elf... and classes warrior and mage. If you try this way, you may use a common event to select the skill the player will learn defining a leveling up trigger and a simple command block, such as:
 
1 if player level is equals to 5:
   2  if player variable playerClass is equals to 0:
        3 if player class is mage:
            4 learn spell human thunder
        3 else
            4 if player class is warrior
                5 learn spell human punch
            4
        3
    2 else
         3 if player variable playerClass is equals to 1:       
             4 if player class is mage:
                 5 learn spell elf thunder
             4 else
                 5 if player class is warrior
                     6 learn spell elf punch
                 5
             4
         3
      2
  1

No, you'll have to wait until code release for that I guess

I think it is possible by editing the InGame.xml file (client and editor/resources/gui). You can manage each box individually, I guess you could hidde hotbarcontainers from 4 to 9 so player only could use hotkeys 1 to 4. I'm not sure if the disable tag works or not so I would just hidde them.

yes it is, you only have to give him both client & editor with your server IP on the resources/config.xml file

You can create rounded-based games. However, there are some limitations:
 
- You must change rounds manually or through timers.
- You can't restart player's progression(you can change the player level's back to 1 but the stat changes won't dissapear, so every time a player levels up to lvl 2 he will get stronger & stronger
- You can restart player's items but you have to do this manually, so you have to create a loop for every single item on that event.
- You have to restart the server manually(or writing some kind of script in order to do this each hour). However, I don't really see the point of this. As a player, there are only a few things worse than getting disconnected from the game for me.

In fact this actually worked. What a shame that I didn't realize before. Thank you.

In fact I think npcs actually are entities. The issue is that events can't focus them yet(except for the no npcs on map condition I think), so you'll need to wait for that.
 
Good luck!