Can I sue either parties for damages

Georgia doesn't allow alienation of affection cases so you can't sue the 3rd party. Conduct however, MAY, in some cases, if properly argued,...

Can these be considered martial assets? And can the rent be considered additional income?

The rent is income. The rest of the question depends on more than we know from your post and you should see a lawyer before filing, as filing may...

Can I add additional creditors at this point and how long does it take to receive the proceeds from the settlement?

Ms. Seymour's answer is perfect. Let me add that you really need a lawyer in your 13. If you have new post-filing debts, you MAY need to dismiss...

What should I do?

Use the State Bar's fee arbitration panel. Get details at https://www.gabar.org/aboutthebar/faq/faqs.cfm?filter=Fee Arbitration

Say a father has 40%, 6 of 14 nights, can he modify visitation to 48 or 50%? What limits a parenting time mod? Decision making?

Unless you demonstrate a strong reason for such a change it's unlikely to be granted.

Can I lose my son if I got a DUI and my son wasn't with me at the time. My x and me have joint custody, but my son was with him

A court certainly might consider a DUI.

You can be separated at the same address (no sexual relations), so yes, this is possible. Get a lawyer to word this properly.

Which party is responsible for the child's medical expenses under these circumstances?

It sounds like your "understanding" is dead wrong. I'd have to read the agreement to be sure, but your interpretation would only be correct if ...

Will my house still be sold if I apply for a year support its schedule for auction 7/2/2016

Years support, even if you could complete it in time, which I doubt, doesn't erase the mortgage. Depending on details we don't have a bankruptcy ...

Will foreclosure make the situation worse?

Many banks refuse deeds in lieu, and foreclosure does have some risk for a deficiency judgment. A smart move would be to see a bankruptcy lawyer. ...