I’m not from the south and use “y’all” all the time. Find it very useful for filling in a gap that English has and slightly faster than saying “you all”. Its gender neutral in my opinion.

Never once thought of it as offensive.

Whatever you can afford for pixel 8 and above, if possible. Those will be supported for longer.

Yes to google maps if you have the play services activated.

No to pay/wallet.

Yes to Android Auto as of recently. The grapheneos team just released a implementation of it.