Dratini 13/15/14 vs 15/15/11 vs 14/14/13?

Doesnt make much difference.
The 15/15/11 will have the higher CP of all. But it's like a 10 CP difference LVL 40.

Is the ordering of stats generally understood as Att/Def/Sta?

Definitely not the 14/14/13. The 15/15/11 is definitely better.

Whether you want 13/15/14 for the best over IV percentage or the 15/15/11 for the higher possible CP is up to you. I'd go with the 15/15/11 but it really doesn't matter.

Just looked at your profile, if Attack was the middle number then definitely the 13/15/14. Will be the best for sure. So looks like you picked the right one.

I would say 13/15/14, but it doesn't matter. Just evolve it until Dragonite. Movesets is more important.

They are all top tier, so evolve them all and take the best moveset. Then likely come back and up the rest anyway .. gonna be hard to find better.