Yes, you need to sign and date the return when filing by mail. Both spouses must sign a joint return, even if only one has income.
The signature is your declaration, under penalties of perjury, that you’ve examined the return and that, to the best of your knowledge and belief, it’s true, correct and complete.
You’ll need to sign and date the return in the areas provided on page 5 of Georgia Form 500.
No, you don’t need to mail in the filing instructions but, as you suggest, send in Forms 500, 525 and 40NR. There’s no requirement in the instructions, which can be found at IT-511 Individual Income Tax Booklet, to include the Schedule C/F Adjustments you’re referring to.
