Can I sue my Ex-Property manager for gross negligence?

[Glenda Barden]

I had a property manager fail to get a signature on the lease of every person over 18 living in my rental property. I have an email sent to me by the owner of the property management company asking me if I wanted anyone else on the lease and I replied, "Yes, I would like everyone living in the house over 18 on the lease". 

Before we were able to get them out of the house, the tenants failed to pay 5 months rent, they left unpaid utility bills, they had a tree cut down and they caused over $10,000.00 worth of damage to my house.

I tried to sue all 3 of the adults in the house, but I was only able to go after the 1 person who actually signed the lease, although all 3 of them are listed as tenants and the other 2 are listed as occupants as well.

Because the property manager did not get their signatures as I had requested,

1. Can I sue my Ex-Property manager for gross negligence?

2. Can I sue them for the portion of monies owed to me by the 2 people they did not get signatures from?

3.  Can I sue the property management company and the 1 Ex Tenant who signed the lease each for half cost of lawsuit?