Will Derrick Henry get fined for his red shoes?

He won’t be fined because red is one of the Titans’ team colors. It’s literally in their logo.

From the NFL rulebook...

Rule 5, Section 4, Article 3, Item 7
Item 7. Shoes. Shoes must be of standard football design, including “sneaker” type shoes such as basketball shoes, cross-training shoes, etc. A player may wear shoes that are black, white, or any Constitutional team color, or any combination of black, white, and a Constitutional team color.
The Titans official team colors are listed as navy, Titans blue, red, silver, and white
https://operations.nfl.com/the-rules/2020-nfl-rulebook/#article-3.-
Kamara wasn’t fined. I think the NFL realizes the free spirit thing is good
If I’m not mistaken, I don’t think fines are handed out until Tuesday. So there’s still a very good possibility he’ll be fined.

But unless he was granted permission to wear them, I think a fine is nearly 100% guaranteed considering neither green or red are one of our team colors.