Can a potential investor really uphold that we had committed ourselves to their terms by referencing a vague email conversation?

What you are doing may be subject to securities laws and regulations. A consultation with a securities lawyer would be wise.

Do you have an attorney that deals with mesh for incontinence? The manufacturer is Gore.

You can use the find a lawyer tool on this site, or google, to search for lawyers in your area.

I would be surprised, but each state's laws are different so please check with a local lawyer ASAP.

Can I sue my old doctor for being lazy about identifying a birth defect in my unborn child?

Unclear whether earlier identification would have made any difference. A local lawyer can review and advise.

Can I use information used in an NDA for my own project?

NDAs typically restrict use. Have a lawyer review the agreement, especially if it covers "a million" things.

Do I need any permits/licenses? Do I pay taxes? Will I get shut down? Can I do it 100% legally?

This is a complicated and risky business and requires qualified legal counsel to do it right.

How can I start proceedings against this company in White Plains, NY? And can I subpeona the full signed contract

A lawsuit can be filed. A local business litigation lawyer can assist.

How do I collect against the assets of a llc that is owned by the two people who I have a judgment against?

In many states, a charging order is needed, but FL may be different. Check with a local lawyer.

Can I sue them for selling my pictures to someone else even though the person bought it back

Even frivolous lawsuits get filed.

Can you sue a drug manufacturer when you have serious life changing side effects?

Certain antibiotics may have this as a side effect, so checking the instructions may be a factor. If it's not a defective drug case, it could...