I don't know how flexible they are at Universal (we don't have kids)but:
Flight of the Hippogriff - Children between 36"-48" must be accompanied by a Supervising Companion.
They aren't being inclusive of the number 48". 48" and above can ride alone. From 36" TO 48" (up to) needs an adult.
Ugh at height and age limits and how to say them. This was the bane of my existence with zoos when my son was little; one zoo said it one way and the other zoo said it another, and I ended up just saying "he's x years, is he free still?" LOL.
Or like with airlines and lap babies. Some truly do think that a 2 year old can still be a lap baby, because it says 0-2...but 2 is the end of it. A 2 year old has a paid seat.
Or the Oceaneers Club/Lab on
Disney Cruise Line but the OPPOSITE way. My cousin thought her son coudln't be in there anymore, and we arranged a whole trip as a "last time the cousins can be together in the kid's club" thing, because she read 3-12 as ending at the 12th birthday. But
DCL means it with the full year of being 12 included. So the 13th birthday means you're not in the club/lab anymore
See what I mean? Some places mean one thing, others mean the other.
DS was 48" during our trip, and one I figured out the solo height thing, he rode alone...