Well that was at least an interesting read. Always find it facinating how these things tend to progress. At any rate thanks for some ideas on Sheik basics, even if I don't use this "combo" (not trying to start a debate here) for anything more than "hey guy, look what I can do". Just plain learning that sourspot Bair has stun properties was news to me. As a (terrible) Zelda main, anything I can learn to improve my Sheik game helps round me out.
Keep poking at it. Ive found huge debates over small variations in DI and SDI only apply when something is clearly anticipated (i.e. theres no way Falco is following his chaingrab off the ledge with anything BUT a spike against my Link). Imo, a footstool jump of any kind is like a PAWWNCH to the ego, and should be used for sheer WTF factor. Though it seems evident that this combo or anything like it will be restricted to a handful of characters, I like toying with the idea of chasing a suprise ftilt footstool with a Bair or needles in general.
Thanks for the tidbits everyone.