Were there other Shredders before Oroku Saki?
 

So it was mentioned that the helmet Shredder wears is the very same helmet the Foot clan leader has been wearing since it's inception, does this mean the Shredder mantle existed before Oroku Saki or did they just wear the helmet without any fancy title?

Looksmore like 'The Shredder' is a self imposed title in the Nick series, then something handed down.

Anyone using an armour with blades fits to use the title "Shredder" if he or she wants, not not much of a big deal (except in the 2003-2009 series).