The seated straddle that then arches back to the handstand on the ground has two people on it, but there’s a rule 3-3-6-e-3 on page 19 that says a top person can’t go directly to an inverted position on the floor from prep level or higher. We’ve always discussed that on the rules committee as being from an actual prep, where she would be inverted already at shoulder level, but I see that the rule says “prep level”. We’ve allowed flatbacks and prone positions to go to handstands forward and backward, in part because they aren’t unsafe, and because you can argue that they aren’t really inverted until the shoulder gets below the waist, which usually happens just below the prep level. This seated straddle that lays back is basically the same thing. I wouldn’t rule that as being illegal.