Creatures that are “fetched” to your hand, as per cards such as Chord of Calling and Gather the Pack, do gain Riot from Rhythm of the Wild.
They do not get to choose between Haste or +1/+1.
A fetched to hand creature is automatically given +1/+1 when it enters the field whatever you last chose for a non-fetched creature. So if you chose Haste for a drawn creature, any fetched creature played before the next drawn creature is given Haste without a choice, and vice versa.
I can confirm a similar problem. When my creatures gain Riot from Rhythm of the Wilds, whatever choice I made on my very first Riot (in my case, +1/+1) became the default choice for all my creatures for the rest of the game. And this is AFTER my first Rhythm was blown up and I played a second one.