Why won't a transaction with 888/byte confirm after 11+ hours?
It won't confirm because the grandparent and parent of your child transaction aren't confirmed. The grandparent transaction was also paid with a really low fee(51.573 sat/B).  

I did the math for you.


Grandparent + parent + child = total transaction size:
3878 Bytes + 226 Bytes + 225 Bytes = 4329 Bytes

Add up all paid fees:
200000 Sat + 200000 Sat + 200000 Sat  = 600000 sat

Divide total paid fees with total transaction size:
600000 / 4329 = 138.6 Sat/B

Subtract to find difference needed:
450 Sat/B - 138.6 Sat/B = 311.4 missing Sat/B



To sum it up.
On average, the three transactions were paid with a fee of 138.6 Sat/B each.
The fee needed to confirm within 6 blocks is presumably around 450 Sat/B right now.
So the three transactions are short 311.4 Sat/B to reach the target of 450 Sat/B.