To answer in what I can do:
- ET, Curious George, Jurassic, and Frankenstein Parking all are about a 5-6 minute walk from the main entrance. ET, Curious George and Jurassic will require you to walk into CityWalk, as there will not be any form of tram transit to take you from the respective parking structures. Frankenstein is directly underneath DMMM, and it's walking path is direct and simple to get to the Hub security checkstands.
- For the walk as you enter the park to Lower Lot, it takes about 12 minutes to get down to the lot itself, and about 3 if the crowds are favorable (as you enter the Lower Lot to SNW itself, to preface that bit). As you are going at opening, it shouldn't be so bad, but do not be surprised if they use the Transformers queue to hold people up for a small bit
- For Toadstool Cafe, you have to be within the property to begin with on the USH app. There is a third party link that I know is somewhere, but I can't find it for the life of me
- If you are planning to get Power Up Bands for you and your party, there are locations outside of 1UP-Factory (The Lower Lot Character Shop next to Jurassic World, the Studio Stores inside the park and CityWalk, Feature Presentation directly next to the Studio Store inside the park, and the Super Nintendo World Store in CityWalk).
As far as wait times, I can't give a guarantee on the matter (As I have not been there in person and have had others help); but keep in mind that for Stand-By, there are two separate preshow sequences (and the Single Rider bypasses both altogether). And if you wanted to get Universal Express just for Mario Kart, as of this time USH is not accepting Universal Express as valid entry into the priority lines.