Shoutout to @ThomasPussyCat on Twitter for finding videos on Vimeo of Super Nintendo World's mini site
The Mario Kart ride, which according to this is potentially named "Mario Kart: Koopa's Challenge" is described as the following:
"A number of courses full of surprises, appear in front of you with the latest technology unique to the park!"
"Ride Time: ~5 minutes
Number of Riders: 4
Height Restrictions: 42" (106.7cm)"
The Yoshi ride, potentially named "Yoshi's Adventure" is described as the following:
"Get on Yoshi's back, follow Captain Kinopio and set off on a treasure hunt adventure, look at the mushroom kingdom from Mount Beanpole and have fun!"
The area's restaurant will potentially be named "Kinopio's Cafe"
The companion mobile phone app which might be named "Mobile Mario" is described as the following:
"Link your smartphone to see play history, coins, and digital stamps! Game data can also be accessed at special checkpoints."
"By linking in with your smartphone you can take your fun to the next level. Turn your journey to Super Nintendo World into a super game. Collect coins and stamps and check your ranking. Climb to the top of the table to be number one!”
Sources: https://vimeo.com/401175263 and https://vimeo.com/401219451 and https://vimeo.com/401522524 and https://vimeo.com/401523911 and https://vimeo.com/401526495 and https://vimeo.com/407823937 and https://vimeo.com/407824807 and https://vimeo.com/407827985 via https://twitter.com/thomaspussycat/status/1290847963061735424 and https://twitter.com/tvmaniaco_tvps2/status/1290890353168482304 and https://twitter.com/tvmaniaco_tvps2/status/1290890379198369798