Deciding between GA and CA for incorporating
If your partner is in Georgia you might as well register your company in that state, because its faster and cheaper to form and maintain. Once you are ready to hire you could register that GA company in California as a foreign entity.
You can open a bank account in any state, however its a bit easier to do in the state of formation. If you want to open a bank account in California for your GA company you might need to present the bank with a letter from your company's CPA stating that this company does not do any business in California (to avoid having to register the company in that state until you are ready).