Hey there!
1 - default mlrs are used here, and the damage from them is default, but mlrs missiles have this peculiarity: they do not always reach the ground, so damage to buildings does not always occur. If I understand correctly what you are talking about
3 - this setting is already there. Also, MLRS missiles do not always reach the target, this is their feature
4 - you can adjust this using this setting - "Rate of fire"
5 - I checked, it works fine. Am I correct that you can drop three supplies in a row even if the cooldown is set to 10 seconds?
9 - As far as I know, my plugin appeared earlier. Perhaps you need to rename other similar plugins
2,6,7,8,10,11,12,13 - thanks for the suggestions to improve my plugin, maybe I'll add it later