What is the possibility of the USPTO granting trademark to a name of a business already exists with similiar services.

If you file a state trademark application, the Georgia Secretary of State will not look at any federal registrations in order to grant you a...

As noted, your copyright exists when you fix it in a tangible medium.

Ensuring I am not infringing a patent

You should seek out patent counsel and have them perform both an infringement analysis/opinion of the patent you are aware of, as well as a freedom...

Can I patent yet or no?

As long as you can describe your invention with sufficient detail that a person of ordinary skill in the art would be able to understand and make...

It will depend greatly on the specific facts of your situation. Assuming you mean a federal registration when you say "trademark," that...

Can I be pursued by a copyright holder for infringement for selling a vintage piece online? For example, a Moulin Rouge poster?

If you are merely reselling an item you own, that is not copyright infringement. Whatever rights the original owner had regarding the sale of the...

Can an ex-partner from my LLC copyright work and IP after his voluntary withdrawal?

This will depend on the agreements you have in place. Seek Oregon copyright counsel to help you with this.

Will an unauthorized use of motor vehicle ever change to be reported stolen?

Changing to criminal, as this is not an intellectual property question.

Can someone use my photo in an advertisement without my permission?

Your right of publicity is separate from the photographer's copyright. While it is likely true that the photographer owns the copyright, it is not...

Can you take two generic items (i.e. eraser and chalk) and created a new item to sell? If so, do you need permission?

If you are not using an item currently protected by a patent, and you are not using a trademark of a third party, I do not see any issue with that....