I wont argue on the neo-classical end but as far a speed shreding... you've already excluded the rockers but they were still shredders. I would put Eddie in there for sure and he even hit on some classical elements, different as he is from Yngwie. But for shrear shredding, Maclaughlin and especially DiMeola were far earlier than Yngwie and most know Yngwie listened to DiMeola. Then there was Zappa, no sloutch and a guy Jan Ackerman from Focus who excluding song writing blew most of the hardrock shredders out of the water. He may very well be the one deserving first credit for applying
some classical elements to "rock". Then I dont know the history of Paco De Lucia but geeze... he shred.
I see what you mean in this strict context by saying "He's the guy that defined shred" but you probably left out some important words like "metal" and also stressed the word "period" and its just imposible with DiMeola floating around since 1973/4 and ignoring all other guitar players through history including jazz, blues and possibly classical (I wouldnt know) who always have seemed to try to play as fast and awesomely as they possibly could.
Then of course your origional shredders were violinists... (ignoring piano players)... whom Yngwie nearly cloned. None the less hats off to Yngwie for his undeniable contribution to
metal
BTW - I have NO Uli and would like some recomendations, probably post Scorpions