Have a look at this product:
https://www.leevalley.com/en/hardwar...76,61995,61646
It can be installed in a 7/8" x 7/16" dado with counter sunk screws through the apron (plus glue). I would think that will provide enough pull out strength for what you'll need, short of someone sitting on the accessory. As for bending moment force, the width of the apron and braces under the accessory should handle it. Just don't make the accessories too large to encourage light loads. Bracing behind the apron would also stiffen this up.
I have a few shop jigs that use this product to make adjustable fences and clamping points. There is also a slightly smaller 1/4" variant.
Only real down side is that they will be more visible than the oak. Some paint could reduce the visibility, or just make it 'part of the design'.