Yes, iPhone 8 does have the stereo speakers.
Yes, iPhone 8 does support wireless charging.
Yes, iPhone 8 does have the OTG support.
Yes, Apple iPhone 8 does have the OIS. It helps greatly with blur in the event of shaking hands or dim lighting and the larger sensor consistently picked up more light for better low-light photos.
No longer the gold standard, the iPhone 8 is still all the phone you need.