4 months = 5,600RD overstay fee. If you have been here just 4 months, your are only 3 months over and owe 3,500RD. Count the days since your entry stamp, under 120 days you owe 3,500, over 120 days = 5,600.
If it's a renewal, the terms of the last contract should not change. unless it's your desire as landlord. If the tenant signed to those terms before, why not again? Don't let the lawyer decide for you. In the end the lawyer will look out for himself.
The armed gangs are used to pushing around unarmed, frightened civilians. A secure base, with machine gun emplacements manned by troops, snipers posted, claymores on the perimeter.....not the games the gangs are accustomed to.
The first 200 will be enough to secure the base being built, perhaps secure the airport also. Don't expect them to engage unless the gangs attack the base.