Yes, you can use the old AirPods with the new iPhone 8.
Yes, you can record 4K videos with iPhone 8.
Yes, iPhone 8 does support wireless charging.
Though Apple never mentioned the battery capacity on their website, during our review of the device we found that iPhone 8 does have 1821 mAh Li-Ion battery.
No longer the gold standard, the iPhone 8 is still all the phone you need.